COMPARISONS BETWEEN PULLETS HOUSED EN CAGES, ON A SLATTED FLOOR AND ON A LITTER FLOOR Thesis for the Degree of DH. D. MICHIGAN STATE UNIVERSITY Hugh Swaney Johnson 1961 THES'S This is to certify that the thesis entitled COMPARISONS BETWEEN PULLETS HOUSED IN CAGES, ON A SLATTED FLOOR AND ON A LITTER FLOOR presented by Hugh Swaney Johnson has been accepted towards fulfillment of the requirements for Ph-D- degree in Poultry Science MW Date Feb. 22, 1962 0-169 LIBRARY Michigan State University 81. are Per ext ABSTRACT COMPARISONS BETWEEN PULLETS HOUSED IN CAGES, ON A SLATTED FLOOR AND ON A LITTER FLOOR by Hugh Swaney Johnson In recent years there has been considerable interest in keeping laying hens in cages and on slatted floors. Many persons and organizations have unduly glamorized and dis— tributed misinformation about these two methods of laying house management due to the lack of scientific evidence. Therefore, this study was made to ascertain information pertaining to the comparative efficiencies of cages and slatted—floor management for the more severe climate of the area selected. This study was composed of two separate experiments. The first trial, during 1959-1960, measured laying house performances for 305 days, and the second experiment extended for 334 days during 1960-1961. The same strain of pullets was used for making comparisons between laying birds in cages, on a slatted floor and on a litter floor. Factors measured included: (1) egg production, (2) laying house mortality, (3) body weight, (4) feed consumption, 2, . . ”.3... a... a r .u Hugh Swaney Johnson (5) egg size, (6) albumen quality (Haugh scores), (7) shell thickness, and (8) blood and meat spots. In the first study (1959-1960) the pullets were housed in three adjacent pens which each contained 464-square feet of floor area. One—hundred-and-twenty birds were placed in each pen with the cage birds being put in indi- vidual cages which were 8-inches wide and l6-inches deep. A commercial pelleted cage layer feed with a minimum guaranteed analysis of 16.5 percent protein was fed all groups both years. No culling was practiced and only dead birds were removed from any of the pens. During the second study (1960-1961) the number of birds in each pen was increased to 200. In the cage room, one bird was placed in each of 40 cages and two pullets were put in each of 80 cages. These were the same cages that had been used the previous year. Dead birds were replaced with stock which was unused at the beginning of this trial. On three consecutive days of every month eggs from each pen were weighed and the albumen quality, shell thickness, and blood and meat Spots recorded. For both of these studies, the cage layers produced a total of 62,151 eggs, those on the litter floor laid 61,940 and the slatted-floor group produced 56,239 eggs. Hugh Swaney Johnson During the second year of this work, the pullets in indi— vidual cages laid at a rate of 63.13 percent while those housed two per cage produced at a rate of 60.99 percent. These latter two figures are based on the total number of birds in cages. A statistically significant difference in egg production was obtained both years between cage and slatted-floor birds. Also a significant difference was observed the first year between litter-floor birds and those on the slatted floor. Mortality was higher during both studies on the slatted floor than it was among the other two groups. The per- centage of deaths was lower in single-bird cages than in two-bird cages. The weight of birds in cages was greater at the end of the laying period than for those birds maintained on either a litter floor or slatted floor. Larger eggs were laid by the cage birds than by either of the other two groups. Both studies revealed this difference to be significant at the one-percent level. Interior egg quality, measured in terms of Haugh units, was practically the same among all groups. The cage layers produced eggs with slightly thicker shells than those produced by the other two groups. Hugh Swaney Johnson Blood spots and also meat spots were detected most often in the eggs produced in cages. A significant difference was noted in the incidence of blood spots between the cage eggs and those produced by slatted—floor birds. COMPARISONS BETWEEN PULLETS HOUSED IN CAGES, ON A SLATTED FLOOR AND ON A LITTER FLOOR BY Hugh Swaney Johnson A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Poultry Science 1961 . W'- ii ACKNOWLEDGEMENT Deepest appreciation is expressed to Dr. H. C. Zindel, Head, Poultry Science Department, who supervised this study in addition to directing the author's graduate program. Thanks is also due Drs. Henry Larzelere, Merle Esmay and Theo Coleman for their helpful suggestions and con— structive review of this thesis. The writer is indebted beyond words to his wife, Carolyn, for her encouragement, understanding, sacrifice and patience during the period of his graduate program. The endless hours she spent on the clerical portion of this report deserves special praise. Also sincere gratitude is extended to Dr. William Baten of the Agricultural Experiment Station for his advice and direction in planning the statistical portion of this analysis. In addition, a note of thanks is offered Dr. L. R. Champion for his helpful assistance after the retirement of Dr. Baten. Finally, without the fullest cooperation of the poul— try plant employees and other personnel in the Poultry Science Department, this thesis would not have become a reality. II. III. IV. VI. VII. VIII. IX. TABLE OF CONTENTS ACKNOWLEDGEMENT . . . . . . . . TABLE OF CONTENTS . . . . . . . LIST OF TABLES . . . . . . . . . LIST OF FIGURES . . . . . . . . LIST OF APPENDICES . . . . . . . INTRODUCTION . . . . . . . . . . REVIEW OF LITERATURE . . . . . . PROCEDURE RESULTS . Experiment I--l959-1960 l. 2. 3. Egg production . . . Mortality . . . . . Body weight . . . . Feed consumption . . Egg size . . . . . . Albumen quality . . Shell thickness . . Pen temperatures . . Experiment II--l960—l96l l. 2. Egg production . Mortality . . . . . Body weight . . Feed consumption . . Egg size . . . . . . Albumen quality . . Shell thickness . . Blood and meat spots Pen temperatures . . Page ii 23 35 11' i '1‘ l.§fl.‘fli.'lil flip“: s..- {.1 J1: ... .. 1 w Amfiul Wllfuudnnrbwrfi. . . . . . I. S . - . .. .. . s .. . . 2.. . .s .. S r . .A. O O r. a. sly,» p. ...1\ XII XII. XIII. DISCUSSION CONCLUSIONS, RECOMMENDATIONS AND SUGGESTIONS FOR FUTURE STUDIES BIBLIOGRAPHY APPENDIX iv Page 109 122 128 133 Table 10. 11. 12. 13. LIST OF TABLES Page Pelleted all-mash laying mash (Farm Bureau) . . . . . . . . . . . . . . . . . . . 34 Monthly egg production in total numbers of eggs--l959—l960 . . . . . . . . . . . . . . . 43 weekly percentage egg production based on hen—day basis-—l959-l960 . . . . . . . . . . 44 Analysis of variance and studentized-range test on egg production--l959-1960 . . . . . . 46 Total number of death losses by months 1959-1960 0 o o o c o l I I o a a a o e a I a 47 Causes of mortality during the 1959-1960 laying season . . . . . . . . . . . . . . . . 48 Statistical analysis of mortality in the various pens by use of the t-test--1959—l960 . 49 Analysis of variance on initial weights of pullets as measured on September 23, 1959 . . 50 Analysis of variance on final weights of pullets as measured on August 1, 1960 . . . . 50 Monthly and yearly feed consumption in pounds 1959-1960 0 o a I o o o a a o o I o e a o o c 51 Average egg size in grams as measured twice monthly—_1959_1960 o a o o o o o u o o o o a 52 Composite distribution of egg sizes in per— centages according to U.S.D.A. Standards for Consumer Grades——l959—l960 . . . . . . . . . . 53 A t—test analysis on egg size as measured twice monthly during the 1959—1960 laying season . . . . . . . . . . . . . . . . . . . . 54 I. . t it t . i t i ‘ ~ , . Elwin. r4 m . , (at-i v 1,. at i ‘1 l .mi «. _O( ...t ... ,h ,‘., ¢ ‘1‘ ..n \\ . 1 ,. ., 3...... . nu .. 21, . u. . : ...,.&... \mfififipfi: . 2:. .... .44.. a)... VA» . e , a v...ru..a\qu_..1Q. Uwvv... 3.3.. m n , , v , . . . syn??? ._:;.,,..i_ o... .l. ...¢..., .2 at 1:14 9ST. l...‘ .9 . I . . . I . l o . . _ J I. . .. i ‘ . , .. u . -1 . a .r. ,. ... ,r . .L t! . u .— ‘ t: t, , . .. 4 2.... .. . l. , . . o Table 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. vi Page Average Haugh unit scores as measured on eight different dates in 1960 . . . . . . . . 55 Analysis of variance and studentized—range test comparing Haugh unit scores--l959—l960 . 56 Average shell thickness in fractions of an inch as measured on three dates in 1960 . . . 57 Analysis of variance and studentized—range test on shell thickness--l960 . . . . . . . . 58 Average monthly pen temperatures as recorded daily at 8:00 a.m. and 4:00 p.m. in degrees Fahrenheit--l959—l960 . . . . . . . . . . . . 59 Monthly egg production in total numbers of eggs--l960-l96l. . . . . . . . . . . . . . . . 75 weekly egg production in percent based on total number of birds—-l960-l96l . . . . . . . 76 WEekly egg production in percent for single and two-bird cages based on total number of birds and hen—day basis--l960—l96l . . . . . . 78 Analysis of variance and studentized-range test on egg production during the 1960—1961 laying season . . . . . . . . . . . . . . . . 80 Total number of deaths by months—-l960—l96l . 81 Causes of mortality during the 1960-1961 laying season . . . . . . . . . . . . . . . . 82 A t-test comparison between the various pens relative to mortality during 1960-1961 . . . . 83 Analysis of variance and studentized—range test on initial weights of pullets as measured on September 1, 1960 . . . . . . . . 84 Table 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. Comparison between initial weights of pullets on September 1, 1960 using the t- test-‘1960'1961 o o o o u I o o o a I I 0 Analysis of variance and studentized-range test on final weights of birds as measured on August 1, 1961 . . . . . . . . . . . . Monthly and yearly feed consumption in PoundS_—1960-196l o o a o o o o o I a o - Average egg size in grams as measured 3- consecutive days monthly during a lO-month period-~1960-l96l . . . . . . . . . . . . Composite distribution of egg sizes in percentages according to U.S.D.A. Standards for Consumer Grades-—l960—l961 . . . . . . A t-test analysis comparing egg size as measured 3-consecutive days monthly during a lO-month period—-l960—l96l . . . . . . . Average Haugh unit scores for each date and month during the 1960-1961 laying season . Analysis of variance for a random selection of Haugh unit scores measured during the 1960-1961 laying season . . . . . . . . . Average shell thickness in fractions of an inch as measured during the 1960-1961 laying season . . . . . . . . . . . . . . Analysis of variance and studentized-range test for a random selection of egg shell thicknesses measured during the 1960-1961 laying season . . . . . . . . . . . . . . Number and size of blood and meat spots detected in broken-out eggs for 3— consecutive days monthly during a 10— month period-—l960—l961 . . . . . . . . . Page 85 86 87 88 9O 91 92 94 95 97 98 o I o. Table 38. 39. 40. 41. A t-test analysis of all blood and meat spots detected in broken-out eggs—-1960- 1961 o I o c o o o c a a o A t—test analysis of all blood spots 0 detected in broken-out eggs--l960-l96l . Average monthly pen temperatures as recorded in degrees Fahrenheit daily at 8:00 a.m. and 4:00 p.m.—-l960—l96l . Average monthly temperatures in degrees Fahrenheit as recorded at the Lansing, Michigan weather Station . viii Page 99 100 101 121 . —.. 4.. . , . . . , .. 1.x 3,. «A A: 1.. .. i1. . ‘ ‘.}..ffi .1. . . .2 . _ . -1; .. 9.. . .a .11.. A..... . -. . c- .A.....,.,...... .10 if»? .39.... .. tin: , . . t. .1 .6.” new??? . .. . v .v. . .u r... . EC: 1 . Figure 1. 10. LIST OF FIGURES Egg production in percent by weeks based on hen-day basis for birds in cages and on slatted floor and litter floor-—1959—l960. Average egg size (grams) as measured twice montle--1959_196O o a o o a n o I o a o 0 Composite distribution of egg size—-l959- 1960 I O O I O O O I O O O O O O O O O C 0 Egg production in percent by weeks based on total number of birds in cages and on a slatted floor and litter floor--l960-l96l. Egg production in percent by weeks based on total number of birds in single and two—bird cages——l960-l96l . . . . . . . . Egg production in percent by weeks based on hen-day basis for birds in single and two-bird cages--l960-l96l . . . . . . . . Average egg size (grams) as measured 3- consecutive days monthly--l960-l961 . . . Composite distribution of egg size--l960- 1961 O D I C O O O O I I O O O O O D O O 0 Average albumen quality (Haugh units) as measured 3-consecutive days monthly-—l960- 1961 I D I O I O O O I I I O I I D O C I C Average shell thickness as measured 3- consecutive days monthly--l960-l961 . . ix Page 60 61 62 102 103 104 105 106 107 108 Appendix 1. LIST OF APPENDICES Page Chemical analysis of pelleted all—mash laying mash (Farm Bureau) . . . . . . . . . 134 Analysis of variance and studentized- range test on egg size as computed on alternate months during the 1960— 1961 laying season . . . . . . . . . . . . 135 Analysis of variance and studentized- range test on albumen quality (Haugh scores) as computed on alternate months during the 1960-1961 laying season . . . . 140 Analysis of variance and studentized- range test on shell thickness as computed on alternate months during the 1960-1961 laying season . . . . . . . . . . . . . . . 143 Equipment depreciation cost per dozen eggs produced during the 1959-1960 laying season . . . . . . . . . . . . . . . . . 148 ‘35. INTRODUCTION In recent years, there has been considerable interest in keeping laying stock in cages and on raised floors made of wood slats or laths, commonly called slatted floors. Along with this interest, there has been a con- siderable number of questions asked. The most prevalent question being—-"How does egg production compare between birds housed in cages, on a slatted floor and under litter-floor management?" Personal opinions and observations have been used to influence producers and prospective producers to use cages or slatted floors in their poultry operation. Only in limited instances has experimental evidence been pre— sented comparing these two methods to the conventional litter-floor type of management. At the same time, poultry department staff members from colleges and universities have been uncertain whether or not to recommend these innovations due to the lack of scientific evidence. This hesitation has prompted many individuals and organizations to unduly glamorize and distribute misleading information about cages and slatted floors. I ‘ . I -‘ 3..- ~.’ t‘"~;‘-‘ A The idea of keeping laying hens in cages probably originated at the Ohio Agricultural Station in 1924 when Professor D. C. Kennard began a series of tests with wire cages holding four birds each (Hartman and King, 1956). In 1926, Kennard initiated tests with single- bird cages lB—inches square. He discovered that chickens kept in cages laid well and produced strong shelled eggs with practically no loss from breakage, that the mortality seemed to be less, that roosts and nests were not needed, and that the wire floors did not make the feet of the birds sore. At the beginning of the thirties, various manufacturers throughout the United States put out individual cages arranged in three decks. Interest remained high for a few years and it was estimated that by 1935 a quarter of a million such cages were sold in southern California (Hartman and King, 1956). However, ventilation troubleS, high initial cost and the extra labor required for their operation caused many of them to be discarded. Immediately preceding World War II, a large number of cage plants were established in southern California. The war period brought further expansion to a virtual standstill but immediately after the war interest in cages revived and reached boom proportions. L. D. Sanborn, farm advisor in Los Angles county, estimated in 1949 that 20 percent of all the layers in his county were in cages (Hartman and King, 1956). In this same county, it has been estimated that 90 percent of all farms starting egg production since 1945 have been of the individual or wire—cage type (King,' 1952). Many of the nearby counties showed this same phenomenal expansion. During the time the cage method was becoming established in southern California, other producers along the Pacific Coast and in the Southwest were becoming interested. In 1950, D. F. King at the Alabama station began experimenting with cages. His work popularized them throughout much of the South as well as in other areas. Some of the most commonly cited reasons for the pre- ference of cages over litter floors include (Paris and Byers, 1957, and McNiece, 1959): l. Elimination of competition between birds 2. Increased feed efficiency 3. Lower mortality 4. Increased egg production 5. Regular replacements make it possible to operate at full capacity 6. Elimination of cannibalism and pickouts 7. Less trouble with diseases and parasites Equally important are the disadvantages of cages when compared with litter floors. The following are most often enumerated (Paris and Byers, 1957, and McNiece, 1959): 1. High initial investment 2. More dirty eggs may result 3. Increased fly problem 4. Difficulties arising from having different ages of replacement pullets on hand 5. Possibly more blood spots 6. Problem of keeping cages full Maintaining layers on a slatted surface and in a restricted area or on limited floor space is not new. The system has been popular in sections of the Orient for cen— turies. Professor C. Bice at the University of Hawaii brought the system of slatted floors into commercial promi- nence in the 1930's (Skinner and Adams, 1958). His objec— tive was to get the birds off the damp ground and thereby eliminate some of the parasites, mold and disease problems. The present popularity of slatted floors seems to be based on one or more of the following assumptions (anony- mous, 1959): 1. More birds are kept on a given amount of floor space and this in turn reduces the housing cost per dozen eggs produced 2. Eliminates litter expense 3. More efficient use of labor because of the concen— tration of birds and suitability to mechanization 4. Decreased parasite problems 5. Longer life of feeders and waterers 6. No dust problem Once again the so—called disadvantages should be noted as well. These include (anonymous, 1959): 1. Initial cost is high and just as many birds can be housed by other means 2. Ceiling heights in existing houses may make the system impractical 3. Birds are inclined to be more cannibalistic 4. Unless completely mechanized, cleaning may require additional labor 5. Floor eggs are frequently a problem 6. Flies may become a problem in the summer unless pit cleaners are used 7. Possibly less production per hen Expansion of the cage and slatted-floor systems has continued in some areas, but the dearth of factual material relating to them, particularly comparing them to the floor method, leaves many questions unanswered. Therefore, this study was undertaken and is based on the following null hypotheses. 1. There are no significant differences in egg pro- duction between pullets housed in cages, on a slatted floor and on a litter floor. 2. There are no significant differences in egg size distribution between the three systems of laying- house management. 3. There are no significant differences in the physical condition of the birds housed in cages, on a slatted floor and on a litter floor. 4. There are no significant differences between the egg quality factors of shell thickness and interior quality between the various systems of management. REVIEW OF LITERATURE A general tightening of the agricultural economy in recent years has resulted from higher production costs and decreasing margins per unit. It is therefore impera— tive that each farmer and poultryman scrutinize the effects of his management practices on production and attempt to make the proper managerial decisions accordingly. Although this experiment was not designed as a cost study per se, any system that reduces such things as feed consumption and laying house mortality, and increases egg production, must be considered a means for lowering pro- duction costs and thus increasing income. These factors have been involved in some of the claims made by the pro— ponents of the various methods of laying house management as they are compared one with another. To shed more light on such statements the following comparisons were made between cages, slatted floors and litter floors: (1) egg production, (2) egg weight, (3) albumen quality, (4) blood spots, (5) shell thickness, (6) feed consumption, (7) laying house mortality, and (8) body weight. Because little information is available comparing all three of these management methods, this review will be divided into two parts. The first section will compare cages with conventional litter floors and the second part will compare slatted floors with litter floors. Comparisons Between Cages and Litter Floors Egg production. A great deal of work has been done on egg production comparisons between birds maintained on a litter floor and in cages, but in general, results have been contradictory as to whether floor or cage birds laid more eggs. Composite data from two different random sample tests conducted in California during 1959-1960 showed that floor birds laid an average of 270 eggs and cage layers 248. These production figures were based on the number of pullets housed and cover the entire 553 days of the tests (U.S.D.A., 1961). Timmons _E El. (1961) compared equal numbers of Rhode Island Reds and Single Comb White Leghorns in cages and on the floor. They found that Leghorn pullets did better in cages than the Rhode Island Reds, but in both cases, the floor birds laid at a higher rate than those in cages over a period of 335 days. Carlson and Strangeland (1960), using Single Comb White Leghorns and feed containing three different protein levels with and without antibiotics, reported that over a six-month period hens in floor pens laid at a superior rate to those in cages. In another antibiotic study, Sanford (1959) found that floor birds laid significantly more eggs than those in The feeds of the various groups contained (1) no and (3) cages. antibiotic, (2) a single source of antibiotic, combinations of antibiotics. Two research reports from Missouri also showed floor birds to be superior to those in cages. Froning and Funk (1958) reported average production on a hen—day basis for the floor birds to be 237 eggs while their full—sisters in cages laid 224 eggs. All birds were fed an all-mash ration containing l6-percent protein and 860 Calories of Iproductive energy. Funk _£_§1. (1958) obtained data on easgg production for a three-year period and found that 1>:ers housed on a litter floor laid at an average rate of €555.0 percent while those in cages produced at 62.6 percent. Lowry £3 El. (1956), comparing full—sisters in cages ai-'!"«'l11 the floor tallied 167. Gutteridge gt 1. (1944) found that Barred Plymouth Rock pullets in cages laid better than those on a litter 12 floor. They reported the differences to be statistically significant at the five-percent level. Another researcher, Thompson (1939), concluded from four years practical experience in the management of lay— ing hens in cages that, "There was no evidence that the individual caging of the fowls either increased or de- creased the egg yield." Egg weight. The relationship between egg weight and type of laying house management has been studied by a number of investigators. Generally caged layers have been observed to lay larger eggs than birds on a litter floor. Lowry gt_§l. (1956) reported April egg weights over a four-year period to consistently favor birds in cages. In each of the years, the difference was statistically signi— ficant at the one-percent level. Bailey §t_gl. (1959), and Froning and Funk (1958) also found statistical differences at the one-percent level :favoring cage layers. In the work by Bailey gt 3;. (1959), 1:he larger egg size in cage housed birds was consistent in EaJll four strains studied. In three years work at Missouri, Funk _£.31. (1958) observed that birds in cages laid slightly, but significantly, 13 larger eggs than their sisters on the floor. Cage layers laid significantly larger eggs than pullets housed on the floor, according to Sanford (1959), in an experiment in which he fed no antibiotics, a single source of antibiotics and a combination of antibiotics. comparing four strains of laying Mellor gt_§l. (1957), hens, reported that eggs produced by birds in cages were slightly heavier than eggs produced by the same strain held on the floor. In this case, they also observed slight differences existed among strains. No differences were noted in egg size between cage (1961) and Gowe (1956). and floor birds by Timmons _t.§l. Albumen guality. Little work has been done comparing albumen quality of eggs produced by the two methods. Funk gt j;l.(l958) reported albumin quality of eggs produced by hens .in cages to be slightly higher during seven of nine months sstudied; however, the difference was not statistically ss;Lgnificant. This same trend was observed in the 1959- 1.5360 California random sample tests, in which case the fiEaugh unit averages were 76 and 77 respectively for floor Ei11lood spots from caged birds than from those on the floor i.rl results obtained during another three-year test. Jeffery (1945) reported that 7.0 percent of the eggs .E>JT<>duced by Rhode Island Reds kept in cages contained blood Si£><>ts compared with 5.7 percent for those of the same s train housed on the floor. His data also showed the 15 percentage of red meat spots was higher for the Rhode Island Reds kept in cages (20.3 percent) as compared with those on the floor (12.6 percent). Contrary to later results, Jeffrey and Pine (1943) observed a higher incidence of blood spots in eggs laid by hens housed on the floor (11.09 percent) than in eggs laid by caged hens (4.01 percent). No differences between systems of management as far as blood spots were concerned were reported by Timmons t _a__1_. (1961). Shell thickness. Frequent statements have been made that shell thickness is a problem in cage produced eggs. No available evidence was found to bear this out. In fact, both Funk _t gt. (1958) and Timmons gt_gt. (1961) found thicker shells On cage eggs. The thickness of the shells <3eposited by both caged and floor housed hens varied gyreatly during the year, according to Funk gt gt. (1958). fitrwever, they found the shells of eggs laid by birds in (zaiges were thicker eight out of nine months measurements Were made. The difference was not statistically significant, thOugh. 16 Mellor gt gt. (1957) and Walker _t _t. (1958) observed no important differences in shell thickness between the two systems. Feed efficiency. Most experimental work has shown more efficient feed conversion in cage birds than in floor t gt. (1959) found that cage housed birds groups. Bailey required 0.118 pounds less feed to produce a dozen eggs than those on the floor. This difference, although it appears slight, was significant at the one—percent level. Experimental results in Texas showed cage and floor birds required 4.48 and 4.96 pounds of feed per dozen eggs t gt., 1959). Both groups received respectively (Miller a cage layer diet of 18-percent protein during the laying period. During a six-year study, Robertson (1956) observed that <:age pullets required less feed per dozen eggs in each of the six compar isons . Hill 2£.EL- (1957), Berry (1946) and Morgan (1954) also 15c>und it took less feed to produce eggs in cages than on tZIIe floor. Morgan (1954) compiled data during a 40-week £>€317iod and reported feed consumption per dozen eggs was ‘1 - 771 pounds for the birds in cages and 4.99 pounds for the pullets on the floor. : . .. ._ — 9| 41.145. j .. Hymnal} .. y... - , .. .2: .11.. .. . . 4.. s. C E is». 1:. .. in. .m. . . in. .DC. .I If ..._..-.._.. .3 3 . .u. p a. m... g1£§fimmmwnmfifi - 1 17 On the other hand, Timmons gt 2;. (1961) reported feed consumption, measured in pounds per 24 ounce eggs, to be higher for the cage group. Rhode Island Reds and White Leghorns were used in the test and in both instances the additional feed required by the cage birds was statistically significant. Mortality. Almost all the experimental evidence shows floor birds to have higher mortality, and conversely, cage birds to have better livability. Miller and Quisenberry (1959) compared mortality for the first 224 days of pro— duction and found death losses on the floor to be 6.27 per— —cent and in cages 3.35 percent. Their study involved 383 and 328 birds on the floor and in cages respectively. Robertson (1956) reported that floor birds had a higher rate of mortality in five out of the six years he compared (rage and floor layers. Mortality was highest among birds kept on the floor in eaaich of the four years studied by Lowry gt 2;, (1956). The Cij_fference was found to be statistically significant at the C>Ile—percent level in two of the years. Gowe (1955) observed from his work that death losses “fee::~e higher among birds in floor pens than in cages. 18 Mortality in the former group was 24 percent and in the latter 19 percent. Although he noted no trend of any kind in causes of mortality,Gutteridge §£_§l,(1944) found death losses to be highest on the floor (19.5 percent) and lowest in cages (18.6 percent). Several other researchers (Berry, 1946, and Hill _£_§l., 1957) also reported lower mortality in birds kept in cages than on the floor. Higher mortality among cage birds was observed by t al, (1959) and in the 1959—1960 California random Bailey sample tests (U.S.D.A., 1961). Mortality in the latter case was 9.5 percent in cages and 7.2 percent on the floor. Timmons gt a1. (1961) found the death losses to be higher on the floor for a group of Rhode Island Reds, but observed just the opposite effect among similar groups of White Leghorns. Body weight. Experimental data indicate heavier body weights in caged birds than in floor birds. Bailey §t_gl.(l959) found the average body weight of caged birds to be 11.64 grams greater than for similar birds on the floor. These 19 results were obtained after 308 days of egg production and the difference was significant at the one—percent level. t El, (1961) reported that both Rhode Island Timmons Reds and Single Comb White Leghorns in cages weighed more, after 335 days of egg production, than corresponding groups of birds on the floor. Morgan (1954) also reported cage layers to be heavier at the end of 40—weeks egg production. Comparisons Between Slatted and Litter Floors Egg production. Little work has been done comparing slatted and litter floors. The studies that have been done, however, seem to favor egg production on conventional litter-type floors. Osborn _t_§l. (1959) made a six— month comparison between Leghorn type hens housed on litter at three-square feet per bird and wood—slat floors at one- square foot per bird. The experiment consisted of 360 IPullets housed on slats and 127 on litter. Hen—housed Gagg production was 7.2 percent higher (60.2 percent vs. 53.0 percent) for the hens on litter. In another test, Godfrey and Butler (1959) compared Phallets on a slatted and litter floor with one, one—and— th of these experiments. Each pen measured 23 feet 6 iriches by 19 feet 9 inches. Ceiling height was 7 feet 2 inches. 25 A commercial type slatted floor was erected 14 inches above the concrete floor in one of these pens. The slatted floor came in four—foot square sections and each section was constructed of l/2-inchlnrlJ/2-inch hardwood slats. Dowel rods supported the slats which were spaced seven- eighths of an inch apart. Water was supplied by two auto— matic cup type waterers. Stair—step cages manufactured by the Northco Ventila— ting Company were installed in a second pen. Two—double rows of cages were used with each cage being 8—inches wide and l6-inches deep. The height of each cage in the back was 16 inches and in the front 19 inches. Feed and < water troughs were located in front of the cages and ex- tended across the entire series of cages. Michigan softwood shavings provided the litter in the third pen. An initial layer of approximately three inches ‘Mas used with additional shavings being added as needed. 'The watering device consisted of two automatic cup type :Eountains situated on top of a small wire platform. The Same amount of feeder space was furnished in this pen as 111 the slatted—floor pen. Roosts were located in the 1Hitter—floor pen but not in the slatted-floor pen. 26 Each pen had one outside wall which was well insulated and contained a vapor barrier. Two glass windows were located in each pen and a transparent plastic window mate- rial used on the outside to provide double protection. One of the inside walls in each pen faced an enclosed alleyway and the other two walls faced adjoining pens. Therefore, wall exposure in all the pens was exactly the same. There was a total of 464 square feet of floor area in each pen or 3,328 cubic feet. Other Environmental Conditions Exhaust fans with thermostatic controls were located in each pen. All fans were rated at 1500 C.F.M. (cubic feet per minute) against a one—eighth inch static pressure. During the year the thermostat settings were changed from ‘150 F. to 600 F. depending on outside weather conditions. Ifiaese adjustments were made in all the pens at the same time. In cool weather, air was drawn into each pen through fCFur slots in the ceiling located on the opposite side of tlle room from the fans. Each slot opening was 4-inches by 2‘l~inches. Tempered air was brought into the pens via the atrtic. In turn, the air was brought into the attic of the 27 gable roof house through louvers located on the roof. In the summer time, the slots in the ceiling were closed and air was brought into the pens through a screened window in the entry door which opened into the alleyway. Fourteen hours of light were provided daily during both of these experiments. The lighting arrangement consisted of 300 watts of light in each pen. Two 150- watt bulbs were used in both the slatted floor and litter-floor pens. This same arrangement was not feasible in the cage room as the cages formed an obstruction and would not permit an even distribution of light. There- fore, three outlets with 40—watt bulbs were located nearest the outside wall and three outlets with 60-watt bulbs were installed toward the inside alley wall. Originally the pens were to have been cleaned out twice yearly, but several water fountain accidents and a maggot infestation in the droppings from the cage birds caused more frequent cleanings. All three pens were always cleaned out at the same time. Trap nests were used in the slatted floor and litter— floor pens with one nest being provided for each five hens. —WI ’6 . s. k 28 Number of Birds fibused First year. On September 23, 1959, a total of 120 pullets were placed in each pen. Selection was made at random with obvious cull birds being discarded. Floor space per bird amounted to 3.87 square feet in the litter and slatted—floor pens and 0.89 square feet per bird for those placed in cages. Even though this latter figure seems low, it must be remembered that the same number of birds were put in each of the identical sized pens. Second year. Two-hundred pullets were housed in each pen on September 1, 1960. The birds were placed in the various pens at random with the culls being removed. In order to accommodate 200 birds in the cage room, one pullet was placed in each of 40 cages and two in each of 80 cages. Single birds in cages were interspersed to maintain an equal number in the top and bottom tiers of the stair-step cages. The amount of floor space per pullet was 2.32 square feet on the slatted and litter floor, and 0.89 and 0.45 square feet respectively for those in one and two—bird cages. 29 Nutrition The same commercial feed was fed all three groups for the duration of these studies. It was a pelleted 16.5 percent all—mash laying mash with the trade label "Hi— Efficiency Cage Layer." The composition shown in Table l is the formula as it appeared on the feed tag during the 1960—1961 laying season. Two ingredients had been changed slightly from the first year. The amount of soybean meal was increased from 296.26 pounds per ton to 296.38 pounds. Penicillin 10 meanwhile had been reduced from 0.24 pounds to 0.12 pounds per ton. The guaranteed analysis remained the same, though. A feed sample was taken from every new shipment of feed to check on the guaranteed analysis. The results are shown in Appendix 1. The chemical composition was determined by the Agricultural Chemistry Department at Michigan State University until January 1, 1961. After that time, the feed analysis work was handled by the chemical laboratory of the Michigan Department of Agriculture. 3O Characteristics Measured The following characteristics were measured during one or both of these trials: egg production, mortality, bird weights, feed fed, egg weights, Haugh unit scores, shell thickness, blood spots and pen temperatures. Egg production. Trap nest records were kept on all birds 5 days a week for the duration of these experiments. No individual records were maintained on Saturdays, Sundays, and legal holidays. Instead, the total number of eggs collected in each pen on those days was recorded. Floor eggs were recorded separately during the week but on week ends and holidays they were lumped into the grand total. When two birds were kept in a cage the second year of this experiment, egg records were not maintained on each individual, but on the production from the cage. Mortality. No culling was practiced in either one of these experiments. Only dead birds were removed from the pens and these were sent to the Michigan State University Pathology Laboratory for an autopsy to determine the cause of death. 31 During the second year of this experiment when a bird died it was replaced by similar stock held for this pur- pose. This kept the number of birds uniform under each management system. Replacement pullets were housed in a separate litter-floor pen and were the birds left after the various pens had originally been filled. All replace- ments were made at night to prevent undue social disturbances. It should be noted that no replacements were made in any of the pens during the first year of this work. weights. Each pullet was weighed to the nearest one— tenth of a pound when housed. At the end of the respective test periods all the birds were again individually weighed. Feed fed. The feed used in this experiment was delivered in 50—pound paper bags. When a bag was brought into a pen it was recorded on a feed card. Egg guality factors. Records were kept on egg weights, albumen quality, shell thickness, and blood and meat spot incidences. During the 1959—1960 laying season egg size was measured twice monthly from October through July. All eggs 32 laid by the cage birds and those laid in the trap nests by the others were recorded and weighed, to the nearest one-half gram, on the first and third wednesday of each month. Albumen quality-—as measured in Haugh units—-was computed on eight different occasions during May, June and July 1960. Once again all trap nested eggs in the case of slatted floor and litter-floor birds, and all eggs laid by the cage birds were collected one day and broken and measured the next day. The shell thickness was measured a total of three times during June and July at the same time the albumen quality was being determined. The second year of this study, International Business Machine (I.B.M.) cards were used (actual cost $254.36) to record data on egg weight, albumen quality, blood and meat spots, and shell thickness. Three consecutive days every month all the trap nested eggs from the slatted and litter-floor birds and all eggs produced by the pullets in individual cages were marked. After each col— lection, the eggs were stored in a 450 F. walk-in egg cooler until the next day when they were delivered to Anthony Hall and examined. Each egg was broken-out on a level glass plate, which was supported by a metal stand. The albumen height was 33 measured using a tripod micrometer and this figure plus the weight measurement was used to compute Haugh units as a measure of interior quality. Shell thickness was recorded by a thickness gauge calibrated in thousandths of an inch and both shell mem— branes were included in the measurement. All measurements were taken while the shell and the membranes were wet. The incidencescxfblood and meat spots was noted at the same time albumen height was being measured. Size, color and location of these blood and meat spots in the broken—out egg was observed visually with the aid of mirrors located underneath and behind the glass plate while measuring the albumen height. Temperature. The temperature in each pen was recorded by the attendant at 8:00 a.m. and 4:00 p.m. every day. A commercial Fahrenheit thermometer was used in each pen and their agreement was checked periodically. Thermographs were placed in identical positions in the pens on January 25, 1960 and seven—day readings were re- corded until March 7, 1960. 34 Table l. Pelleted all-mash laying mash (Farm Bureau) Ingredients Percentage Pounds Alfalfa meal 2.00 40 Blood meal 1.25 25 Corn 60.00 1200 Dicalcium phosphate 1.75 35 Fat 0.375 7.5 Fish meal 0.50 10 Fish solubles 0.25 5 Limestone 5.81 116.2 Meat scraps 2.50 50 Pulverized oats 10.00 200 Salt 0.44 8.8 Poultry mineral mix 0.05 l 50% soybeam meal 14.819 296.38 Penicillin 10 0.006 0.12 Layer vitamin premix (0.08% soy) 0.25 5 100.00% 2000 Guaranteed Analysis Protein (Min.) Fat (Min.) Fiber (Max.) Calcium (Min.) Phosphorus (Min.) Iodine (Min.) Salt (Max.) 16.5% 3.2% 3.8% 3.0% 0.6% 0.0001% 0.5% 35 RESULTS Experiment I-—l959-1960 Egg production. Individual egg records were started on October 1, 1959 when the birds were 195-days old and were maintained for 305 days until they reached 500 days of age. The total egg production for all pens during this period amounted to 61,729 eggs. Of this total, the litter-floor birds laid 21,506, those in cages 21,369 and the slatted-floor group 18,854 (Table 2). Production is shown for the various pens on a weekly hen-day basis in Figure 1 and Table 3. The slatted-floor birds consistently trailed the other two groups in pro— duction, except at the very beginning and end of the study. The poor production of the slatted-floor birds was especially evident from the sixth to twenty-fourth week or from November to the middle of March. During the entire period of this study, on a hen-day basis, the cage layers produced at a rate of 63.67 percent. This com— pares with 63.18 percent for the litter-floor birds and 57.79 percent for those on the slatted floor. An analysis of variance indicated that the difference between these systems of management was statistically 36 significant at the one—percent level (Table 4). All the birds that died and those that laid less than 50 eggs during the study were discarded before this analysis was made. The latter group was removed because the egg pro— duction patterns indicated they either laid a large num— ber of floor eggs or were ill. When a studentized—range test was applied to these data, it was found both cage and litter—floor birds laid significantly more eggs, at the one-percent level, than those birds housed on the slatted floor. There were no statistical differences between the production of cage and litter—floor birds. The number of eggs laid on the floor by the slatted- floor birds was 2160 and by the litter-floor group 1353 (Table 2) or 16.54 percent and 9.02 percent respectively for the two groups. Mortality. The mortality was highest among the slatted- floor birds and lowest among the litter—floor group during the 1959-1960 laying season. A total of 29 birds died on the slatted floor (24.17 percent) compared with 22 in cages (18.33 percent) and 20 on the litter floor (16.67 percent). The number of death losses during the various months is given in Table 5. 37 According to autopsy reports received from the Veteri— nary Pathology laboratory, the major cause of mortality in all the groups was visceral lymphomatosis (Table 6). Nine birds in cages died from visceral lymphomatosis while seven birds were lost due to this same cause in each of the other two groups. Prolapses and/or pickouts were another important cause of deaths in the slatted-floor pen. The t-test was used for making a statistical analysis on mortality between the various methods of management. No statistical differences were observed between any of the pens. The calculated t-values are given in Table 7. Body weight. When the pullets were moved into their permanent quarters on September 23, 1959 they were each individually weighed. The average weight per bird on the litter floor was 3.90 pounds while these housed on the slatted floor averaged 3.83 pounds and the group placed in cages averaged 3.82 pounds. An analysis of variance on initial weights indicated the populations in the three pens were homogeneous (Table 8). At the end of the study on August 1, 1960 all the live pullets were again weighed. The cage birds were the heaviest and averaged 4.76 pounds each while the slatted— 38 floor group averaged 4.47 pounds and those on litter averaged 4.27 pounds. The statistical treatment involved the use of an analysis of variance and final weights were found to be significantly different at the one-percent level of significance (Table 9). When a studentized- range test was applied to the results, the cage birds proved to be significantly heavier (one—percent level) than those on either the slatted floor or litter floor. No statistical differences were noted between the latter two groups. Feed consumption. The total amount of feed consumed in each of the three pens is shown in Table 10. The greatest consumption of feed took place in the litter-floor pen (9209 pounds) but egg production was also highest in this group of birds. The cage layers ate 9156 pounds and those birds on the slatted floor consumed 9095 pounds. When this was calculated on the pounds of feed per dozen eggs produced, the cage and litter—floor birds required identical amounts of 5.14 pounds. The pullets on the slatted floor required 5.79 pounds per dozen eggs produced. ”-‘-v~ 39 Egg size. The eggs produced by cage layers were heavier than those laid by either of the other two groups. Average size of the cage eggs, as measured twice monthly during the study, was 61.15 grams. The birds on the slatted floor and litter floor produced eggs which averaged 59.54 grams and 59.13 grams respectively. Average egg size for each of the twenty weigh periods and by pens is shown in Figure 2 and Table 11. When a weight distribution was made according to U.S.D.A. Standards for Consumer Grades, the number of eggs from cage layers which weighed Large and above totalled 79.22 per— cent. This compares with 68.21 percent from the litter- floor birds and 67.75 percent from the slatted—floor pullets. A complete distribution of egg sizes as measured by eggs col— lectedtflmee consecutive days monthly, is given in Table 12. This is also shown in Figure 3, except the Jumbo and Extra Large eggs are combined into one group as were the Small and Peewee eggs. They were combined to avoid using very small and disproportionate figures. For a statistical treatment, the t-test was used for making comparisons between the various groups (Table 13). Eggs laid by the cage birds were found to be significantly 40 larger, at the one—percent level, than those produced by the litter-floor group. Caged birds also laid signi- ficantly larger eggs than the slatted-floor pullets. There was no significant difference in egg size between the litter floor and slatted-floor groups. Albumen guality. Eggs were broken-out and Haugh unit scores recorded during the spring and summer months of May, June and July. Interior egg quality, as measured in Haugh units, favored the litter—floor birds with an average score of 75.93. The cage birds averaged 74.53 Haugh units and those pullets on the slatted floor averaged 74.25 (Table 14). An analysis of variance was used as the statistical treatment and a significant difference, at the five— percent level, was observed between pens. The studentized— range test indicated that Haugh unit scores for the litter-floor pullets were significantly better than the eggs from the cage and slatted—floor birds. No difference was evident between the cage and slatted-floor groups (Table 15). Shell thickness. Slightly thicker shells were found in eggs laid by the cage layers than by either of the other r . . _ ' stiff" 41 two pens. The average shell thickness, measured in fractions of an inch, was 0.01337 of an inch for the cage layers. The birds on litter and the slatted floor had shell thicknesses of 0.01289 and 0.01320 of an inch respectively (Table 16). When an analysis of variance was applied to these data the differences between pens were found to be highly significant (Table 17). The studentized-range test indicated that both the cage and slatted-floor birds had thicker shells than those deposited on the eggs of the litter-floor groups. The difference was at the one—percent level of significance between cages and litter—floor birds and at the five—percent level between slatted floor and litter—floor birds. There was no statistically significant difference between the shell thickness of eggs laid by slatted floor and cage birds. Pen temperatures. The average monthly temperature varied only slightly between the three pens (Table 18). Over the entire lO-month period, the lowest average monthly temperature was recorded in February at 4:00 p.m. in the slatted—floor pen (45.970 F.). The highest monthly temperature--80.90o F.—-was in July at 4:00 p.m. in the litter-floor pen. 42 The thermograph recordings from January 25 to March 7 indicated this same uniformity of temperatures between the various pens. In general, the thermograph records showed the lowest temperature during a 24—hour period was around 4:00 a.m. or just before the lights went on. The highest daily temperature was reached about 2:00 p.m. 43 mom.HN Heme w~w.¢a oom.am momo mmma m¢©.ma vmw.wH hmhm ooam bow.oa HMDOB NNoH moo naoa mmsa Hmo Nb N©OH mmma gmm mm mam mash mmsa nwv ooma mmma Ham mm omma mgma mow ova pom wasm mmom vmo mwma mmHN Han moa mama moha mnm ova smoa wmz HNON oao Hawa mHHN wmo vNH mmma vaH bmm mma vmoa Hflumm hmom Hmm coma NNON mam ova wmma Hana ng mwa hwoa noumz mama mmm vmva HNHN nwm NmH Nmma hmna mam MNN maoa humannmm omvm gum puma mmvm mmm Hma mmga smom Nms mom NMOH ooma..:mo gmmm mwn mesa 00mm mom oom Hmma omam mum ovm meH Hmnawoma maem «ms mwoa mgmm Now gga smga mvam mmo mom mema HmQEm>OZ nmflm a NNh mmna boom mom mmH vaH vaN mmo mom coma mmma..poo HMDOB mono pound: ANDOB muse mmmw Umumms Hmpoe mucm mmmm popmmc #003 ImmHB Mwmz Hoon Immufi #003 Hooam IQMHB mmmm mmmu mmmm HOOHMIMODDHA mama HOOHMIUMpumam \\\\\l‘ oomalmmmallmmmm mo mumflfisc Hmuou CH QOHDUDUOHQ 0mm waflucoz .N QHQMB 44 Table 3. weekly percentage egg production based on hen—day basis—-l959—l960 Percent production Dates weeks Slatted Litter Cages floor floor October: 1959 1-7 1 57.02 48.56 62.14 8-14 2 58.10 51.14 64.17 15-21 3 64.05 55.70 69.05 22-28 4 64.36 60.26 68.21 29—4 5 60.86 62.38 66.55 November: 5-11 6 60.50 65.21 67.62 12-18 7 58.77 66.91 67.83 19-25 8 60.68 66.30 67.79 26-2 9 61.05 68.13 69.09 December: 3—9 10 61.17 70.26 70.09 10-16 11 60.76 74.35 70.48 17—23 12 60.47 72.30 72.13 24-30 13 60.32 70.68 72.30 31-6 14 61.49 70.31 68.96 January: 1960 7-13 15 58.02 67.54 69.91 14—20 16 57.40 68.55 70.92 21-27 17 62.39 69.30 71.72 28-3 18 58.04 66.92 66.84 February: 4—10 19 57.79 64.79 61.86 11-17 20 55.54 66.25 62.02 18-24 21 53.21 64.35 61.85 25—2 22 52.23 61.19 60.13 45 Table 3. Continued ' Percent production D t W a es eeks Slatted Litter Cages floor floor March: 3-9 23 48.94 60.30 63.49 10-16 24 49.54 58.53 61.52 17-23 25 52.60 54.68 61.28 24-30 26 55.14 57.11 58.61 31-6 27 51.67 57.53 61.15 April: 7-13 28 58085 62.29 64.62 14-20 29 60064 65.12 63068 21-27 30 61.20 67053 62022 28-4 31 61.78 66.80 64.44 May: 5-11 32 58.97 65.74 64.63 12-18 33 58.13 67.06 62.55 19—25 34 56.72 63.62 60.16 26-1 35 59.34 63.65 60.85 June: 2-8 36 57.71 64.56 59.48 9-15 37 55.28 61.71 57.28 16-22 38 55.90 62.83 57.01 23—29 39 53.42 59.78 56.65 30-6 40 51.48 59.38 54.89 July: 7-13 41 56.20 59.10 53.95 14—20 42 57.77 56.44 53.25 21-27 43 55.57 54.92 50.36 28-31 44 53.30 52.00 50.26 57.79 63.18 63.67 Average {1:3 46 Table 4. Analysis of variance and studentized—range test on egg production--l959—l960 Source of . . S.S. D.F. M.S. F ratio variation Pens 14,168.74 2 7084.37 8.08** Error 228,718.59 261 876.32 Total 242,887.33 263 ** Significant at one—percent level Studentized—range testl 121.37 133.48 139.53 1 l 4 I I I Slatted Litter Ca es floor floor 9 One-percent level: Cages, litter floor > slatted floor Any two means not overscored by the same line are signi— ficantly different, and any two lots overscored by the same line are not significantly different. 47 Table 5. Total number of death losses by months--l959—l960 Numbers Dates Slatted Litter Cages floor floor October, 1959 l l 0 November 2 2 2 December 2 2 3 January, 1960 4 l 3 February 2 l 4 March 2 2 1 April 6 2 0 May 6 3 3 June 3 4 1 July 1 2 5 Total 29 20 22 Table 6. Causes of mortality during the 1959—1960 laying 48 season Numbers cause Slatted Litter Cages floor floor Visceral lymphomatosis 7 7 9 Prolapses and/or pickouts 7 1 - Hemorrhagic causes — 3 l Peritonitis 2 - 2 Impacted oviduct l l l Visceral gout l 2 — Chronic respiratory disease 1 l - Tracheitis — l l Tumors (liver or ovary) — — 2 Nephritis 1 l — Coccidiosis — l - Impacted intestine — - 1 Air sacculitis l — — Chronic cholera - l — Undetermined 8 l 5 Total 29 20 22 49 Statistical analysis of mortality in the various pens by use of the t—test--l959-l960 SLATTED FLOOR and LITTER FLOOR = 0.2417 - 0.1667 0.05182 = 0.07500 0.05182 t = 1.45 N.S. LITTER FLOOR and CAGES = 0.1833 — 0.1667 0.04905 0.0166 0.04905 t = 0.34 N.S. SLATTED FLOOR and CAGES t = 0.2417 — 0.1833 0.05268 _ 0.05840 0.05268 r—r II 1.11 N.S. 50 Table 8. Analysis of variance on initial weights of pullets as measured on September 23, 1959 Source of . . S.S. D.F. M.S. F ratio variation Pens 0.43 2 0.215 0.78 N.S. Error 97.81 357 0.274 Total 98.24 359 Table 9. Analysis of variance on final weights of pullets as measured on August 1, 1960 Source of . . S.S. D.F. M.S. F ratio variation Pens 11.82 2 5.91 9.88** Error 171.11 286 0.598 Total 182.93 288 **Significant at one—percent level Studentized—range testl 4.27 4.47 4.76 l J I I I l Litter Slatted C floor floor ages One-percent level: Cages > slatted floor, litter floor 1 Any two means not overscored by the same line are signifi— cantly different, and any two lots overscored by the same line are not significantly different. 51 Table 10. Monthly and yearly feed consumption in pounds—— 1959—1960 Pounds of feed Dates Slatted Litter Cages floor floor October, 1959 1000 950 1050 November 925 850 950 December 1050 1050 1050 January, 1960 1000 1000 1000 February 950 950 850 March 1000 1050 1000 April 900 950 1050 May 850 900 850 June 700 800 750 July 720 709 606 Total 9095 9209 9156 " . ' '- u 5 ~ - ~. .- . . ’_Lg..._ .4._~.-‘_““_— 4' ~L:—_‘ _ 1___ Table 11. Average egg size in grams as measured twice monthly-—l959—l960 Average egg size (grams) Dates Slatted Litter Ca es floor floor 9 October 7 (1959) 51.11 51.50 52.57 21 53.96 52.33 55.82 November 4 55.12 54.96 57.56 18 56.18 55.74 59.01 December 2 57.52 57.21 59.48 16 58.24 57.68 60.81 January 6 (1960) 58.85 57.68 61.23 20 59.81 58.98 61.21 February 3 60.28 58.39 61.21 17 61.39 60.54 61.65 March 2 62.74 62.36 63.35 16 61.68 61.52 63.86 April 6 62.73 62.61 64.08 20 60.45 59.57 60.40 May 4 63.34 62.69 64.23 18 62.76 61.73 64.79 June 1 63.44 61.58 64.18 15 62.45 62.02 64.85 July 6 62.62 63.37 65.12 20 61.99 62.36 64.48 Average 59.54 59.13 61.15 Table 12. 53 Composite distribution of egg sizes in percen— tages according to U.S.D.A. Standards for Con— sumer Grades——l959-l960 Percent Weight classes slatted Litter Ca floor floor ges Jumbo 4 45 2.48 4.61 Extra large 19.09 19.24 28.30 Large 44.21 46.49 46.31 Medium 27.89 24.86 18.87 Small 3.56 6.36 l 84 Peewee 0 79 0.58 0.07 54 Table 13. A t—test analysis on egg size as measured twice monthly during the 1959—1960 laying season SLATTED FLOOR and LITTER FLOOR 59.64 - 59.27 t: V0.03606 + 0.02955 0.37 0.2561 t = 1.44 N.S. LITTER FLOOR and CAGES 61.21 - 59.27 t— 'V0.02955 + 0.02208 = 1.94 0.227 t = 8.55** ** Significant at one-percent level SLATTED FLOOR and CAGES 61.21 — 59.64 t: 'Vb.02208 + 0.03606 = 1.57 0.2411 t = 6.51** ** Significant at one-percent level MW“ .MI." I’ Table 14. Average Haugh unit scoresl different dates in 1960 as measured on eight Average Haugh units Dates Slatted Litter Cages floor floor May 18 1960 72.88 74.88 72.03 June 1 76.24 77.39 77.20 15 75.05 78.38 74.96 July 6 81.17 81.34 79.58 20 69.73 71.16 69.34 26 70.43 71.59 74.09 27 74.93 74.44 74.02 28 73.89 76.26 74.84 Average 74.25 75.93 74.53 lHaugh units for U.S.D.A. Egg Quality Standards: AA — 72 and above — 55 to 72 B — 31 to 55 C - 31 and below 56 Table 15. Analysis of variance and studentized-range test comparing Haugh unit scores——l959—l960 Source of . . S.S. D.F. M.S. F ratio variation Pens 625.62 2 312.81 3.87* Error 94,635.88 1170 80.89 Total 95,261.50 1172 * Significant at five—percent level Studentized—range testl 74.25 74.53 75.93 I I I I l I Slatted Cages Litter floor floor Five-percent level Litter floor > cages, slatted floor 1 . . . Any two means not overscored by the same line are Signi- ficantly different, and any two lots overscored by the same line are not significantly different. 57 Table 16. Average shell thickness in fractions of an inch as measured on three dates in 1960 Shell thickness (X0.001 = inches) Dates (1960) Slatted Litter Cages floor floor June 15 13.32 12.84 13.58 July 6 12.90 12.85 13.12 July 20 13.33 13.00 13.41 Average 13.20 12.89 13.37 58 Table 17. Analysis of variance and studentized-range test on shell thickness——1960 Source of . . S.S. D.F. M.S. F ratio variation Pens 17.69 2 8.85 7.02** Error 543.71 433 1.26 Total 561.40 435 ** Significant at one—percent level Studentized—range testl 12.89 13.20 13.37 1 l, 1 l | l Litter Slatted Cages floor floor Five-percent level: Slatted floor > litter floor One-percent level: Cages > litter floor 1 Any two means not overscored by the same line are signi— ficantly different, and any two lots overscored by the same line are not significantly different. - . . . I A. I in. . fill o d 1!- ’ 'I 'll I" r! -ll | D I Hit] 0' 1" l.-1 Ii) ) . I‘l‘ . . I I I Ill. I| v .. I w I I: III». I- l I Table 18. 59 Average monthly pen temperatures as recorded daily at 8:00 a.m. 1959—1960 and 4:00 p.m. in degrees Fahrenheit-- Dates Slatted floor Litter floor Cages 8:00 am 4:00 pm 8:00 am 4:00 pm 8:00 am 4:00 pm 1959 OctOber November December 1960 January February March April May June July 53.92 47.60 47.45 47.26 46.00 46.77 54.70 61.81 65.00 68.10 59.65 49.10 48.77 46.97 45.97 48.61 63.24 70.35 75.00 79.60 54.58 49.20 48.48 47.71 46.90 48.10 55.93 61.74 65.60 69.10 59.92 49.93 48.61 46.68 46.41 50.03 64.20 71.13 76.37 80.90 52.71 47.83 48.90 48.23 47.45 48.10 54.34 60.35 65.17 68.13 58.80 49.17 48.65 47.13 46.66 49.52 61.86 68.61 74.30 78.10 60 .Ommemm. ..I «504“. «EFF: oz< moon...— owhbjw 20 024 mmwm Fzmommnu z. ZOFUDn—Omn. 00m mxmw? ¢¢N¢ovmmwm¢n Nmom mNoN .vN NN ON m. o. .v. N. o. m n n . p n p n h p p p h . . b < d u q n n u - n - J u u dI d - - - . mmo431 mza. ><2 muo>.r 0mm3m< mom. Ihzoz oz< uhoz mumo...oo N h. n ON L - w h 1 0. Q. .v _N N \ 41 I V IO SWVHO — 1H9|3M 1-6m .N manor. .l .I III Ill..-| .IIIJII-l 62 .Omm_ummm_IIMN_m 00m “.0 ZOFDmEFmE wtmOQZOO $30 I mood cut: a 0\o _m._ mood... 853m D .x. ¢m.m .. z... o\.. mné o\o Fwd. on u a, a. I. o. n- o. 00000 u... p a .x. 3.3 1...”... 8.”. - A”... $3.3 _ .m wmaoE mmiwwa oz< 4.32m 23.0w! meme...— .n a.» .H... .4... .x. 5.6.. .x. 3.6.. .... R ..\o 5.3. ..\o .m.~n .x. 22m ................HH.............N.....................w..fl....m..... was: «Exu .\. 3 .3 r 026. ems—D... 63 Experiment II--l960-l96l Egg production. Total egg production was practically identical on the litter floor and in cages during the second year of this study. Over a 334-day period, the cage birds laid 40,782 eggs and the litter—floor pullets 40,434. Chickens confined on the slatted floor produced a total of 37,385 eggs (Table 19). The respective per- centages, based on the total number of birds, for the pullets in cages and on the litter floor and slatted floor were 61.05, 60.53 and 55.97. The weekly rate of lay is shown in Figure 4 and Table 20. In figuring the percent production, the total number of eggs laid in a 7—day period was used, except during the forty- eighth week when only a five-day period was covered. It can be seen that the birds on the slatted floor trailed the other two groups, almost without exception, during the 48- week laying period. The litter—floor birds hit a slump about the sixteenth week and fell considerably below the cage layers until approximately the twenty—seventh week. This period of time was between December 15 and March 8. On the other hand, the cage birds maintained fairly even production throughout the entire laying period. 64 A comparison between birds in single and two—bird cages is shown in Figures 5 and 6, and also in Table 21. The percentages used, for the most part, are based on a five— day week as no distinction was made on Saturday or Sunday whether the eggs were laid by birds in one or two—unit cages. The weeks listed in Table 21, therefore, include only a five—day period unless otherwise stated. Figure 5 illustrates egg production in cages based on the total number of birds. The pullets in two—bird cages trailed the pullets in single-bird cages, on a percentage basis, during much of the study. This was especially evident from the tenth to thirty—eighth week. Over the entire 48-week laying period, the pullets in individual cages laid at a rate of 63.13 percent and those in the two- bird units produced at a rate of 60.99 percent. Egg production on a hen—day basis for the pullets in one and two-bird cages (63.26 and 61.22 percent, respec— tively), is shown in Figure 6. The percentages listed are based only on the pullets which originally started in this experiment on September 1, 1960. When a pullet died in a two-bird cage the entire cage was dropped from further consideration as it was not possible, under the conditions of this experiment, to make a distinction between eggs laid 65 by a particular individual in a two-bird unit. The dif— ference in production is slight, however, whether the results are based on the total number of birds or a hen— day basis. An analysis of variance indicated there was a statis- tically significant difference, at the five—percent level, between pens (Table 22). A studentized-range test showed there was a significant difference at the one-percent level favoring cage birds over the slatted—floor pullets. No observable differences were detected between cage and litter—floor birds or between litter floor and slatted— floor pullets. Before computing the analysis of variance, birds that either died or laid less than 40 eggs during the test period were removed from consideration. Floor eggs were less of a problem the second year of this experiment than they were the first. A total of 2075 eggs were laid on the floor by the litter confined birds and 1817 eggs by those birds on the slatted floor (Table 19). This amounted to 7.28 percent and 6.87 percent respectively, based on the total number of trap nested and floor eggs. Mortality. The number of deaths during the second year of this experiment was once again highest on the slatted 66 floor. Mortality amounted to 22.50 percent among the slatted-floor birds compared with 18.50 percent on litter and 13.50 percent in cages. These figures include two replacement birds which died in each of the floor pens and one replacement that died in cages. Including replace— ments, a total of 45 pullets died on the slatted floor, 37 on the litter floor and 27 in cages (Table 23). In the cages, three pullets died in the one—bird units L or 7.50 percent. Twenty-four birds died in the two-bird cages for a total of 15.00 percent. The largest number of determined deaths was caused by visceral lymphomatosis and prolapses or pickouts (Table 24). The cause of mortality in many cases was undetermined even though all the birds were given a post—mortem examination in the Veterinary Pathology laboratory. The t—test was employed to determine statistical dif— ferences in mortality between pens (Table 25). No signi- ficant differences were obtained between birds on the slatted floor and litter floor or between birds in the litter pen and cages. A significant difference at the five—percent level was observed between the slatted—floor pen and cage birds. 67 The statistical analysis was carried one step further by comparing birds in single-bird cages with the two-bird units and also with the slatted floor and litter-floor pens. There was a significant difference at the five— percent level favoring pullets in single cages over the litter—floor birds. Pullets in single cages were superior to slatted-floor birds at the one—percent level. Body weight. The initial weights of the pullets in the various pens were statistically different at the one— percent level of significance (Table 26). When a studentized— range test was applied to these data, it was found that the pullets on the slatted floor were significantly heavier than either of the other two groups. Their average weight was 3.38 pounds compared with 3.26 pounds for those in cages and 3.19 pounds for the litter-floor group. The results of a t-test indicated this same difference (Table 27). Due to the initial weight differences, little reliance can be placed on final comparisons with the slatted—floor birds. However, an analysis of variance and subsequent studentized-range test on final weights did indicate that cage birds were significantly heavier (one-percent level) than their counterparts on the litter floor. Also, the -—-———.v 0'" 68 cage layers were significantly heavier than the slatted— floor birds even though the latter group was significantly heavier at the start (Table 28). Average body weights at the end of this experiment were 4.49 pounds for the cage birds, 4.32 pounds for those on the slatted floor and 3.98 pounds for the litter-floor group. Feed consumption. The largest amount of feed was con— sumed by the slatted—floor birds. They required 16,979 pounds of commercial mash during the ll—month test period. The cage pullets consumed 16,936 pounds while those on the litter floor required 15,795 pounds (Table 29). In terms of feed conversion, the highest degree of efficiency was obtained by the litter-housed birds. They required 4.69 pounds for each dozen eggs produced. Cage layers had a feed conversion of 4.98 pounds and those on the slatted floor 5.45 pounds. Egg size. The eggs produced by the cage birds were heavier than those produced by either of the other two groups of birds. This was the same trend as observed during the first year of this study. 4...... Lhasa; - 69 Average weight of the cage produced eggs was 61.02 grams. This represented a sample of 760 eggs produced by pullets in single—unit cages. Only eggs from birds housed in single cages were weighed as individual production records were not maintained for those pullets in two-bird units. Eggs from the slatted-floor birds averaged 59.65 grams and those produced by litter-floor pullets averaged 57.44 grams each (Table 30). A total of 2810 eggs com— prised the former group and 3050 the latter. The average egg weights by groups for the various months are pictured graphically in Figure 7. This chart shows, except for October, that eggs from cage birds were the largest. They were followed in size by eggs from the slatted—floor pullets and then those produced by birds on the litter floor. A distribution of egg size was made according to U.S.D.A. Standards for Consumer Grades (Table 31 and Figure 8). The Jumbo and Extra Large, and Peewee and Small were once again combined in Figure 8 in order to avoid using very small figures. The exact classification, according to the various weight classes, is shown in Table 31. The t-test was used for making a statistical comparison of egg size between the three systems of laying house manage- ment. A significant difference at the one—percent level was 70 observed between all three management methods. The pullets in cages laid significantly larger eggs than birds on either the slatted floor or litter floor. Also, slatted-floor birds laid significantly larger eggs than those on the litter floor (Table 32). Egg size comparisons in alternate months of this study using an analysis of variance are shown in Appendix 2. Albumen guality. Haugh unit scores, used to measure albumen quality, favored the litter-floor birds. The average score for this pen was 79.72 as computed on 3050 eggs during a lO—month period. The cage birds had an average Haugh score of 78.56 and those birds on the slatted floor averaged 78.53. A total of 760 and 2810 eggs respec- tively comprised the latter two groups. Only eggs from the single-bird cages were used in making these compari— sons. Daily and monthly average Haugh-unit scores for the three groups of birds are shown in Table 33. A graphic illustration of average monthly Haugh scores is shown in Figure 9. It can be seen from this illustration that albumen quality declines with season and/or age of birds. A two—variable analysis of variance was used to compare the Haugh unit scores of the eggs produced in the various 71 pens. One of the variables was the seasons of the year with October, November and December being conSidered one season; January through April was another season; and May, June and July comprised the third season. The other variable was management methods or pen differences. To avoid using a very complicated series of formulas for dis- proportionate numbers, a random selection of 12 Haugh-unit scores was made from each pen for each season (Dixon and Massey, 1951). The selection provided material for a proportionate sub-class of numbers. No statistical dif- ferences were evident between the pens in this analysis. However, a highly significant different was present in these data between seasons (Table 34). An analysis of variance on all eggs during alternate months of this study is shown in Appendix 3. Shell thickness. The pullets in cages laid eggs with thicker shells than birds in either of the other two groups. Average shell thickness for cage layers was 0.01408 of an inch compared with 0.01380 and 0.01364 of an inch res— pectively for birds on the slatted floor and litter floor. These results coincide with results obtained the first year of this experiment. A complete listing of the average 72 daily and monthly shell thicknesses are listed in Table 35;. The monthly averages are, in turn, graphically presented in Figure 10. The statistical treatment, a two—variable classification of an analysis of variance, indicated that eggs from cage birds had significantly thicker shells than those deposited on the eggs by birds on the slatted floor or litter floor (Table 36). The seasonal variation was significant at the one-percent level. The same random selection was used for making shell thickness comparisons as had been employed for comparing Haugh scores. Statistical treatments for shell thicknesses every two months of this experiment are listed in Appendix 4. Blood and meat spots. The percentage of blood spots was highest in the eggs from cage layers with 3.29 percent. The litter-floor group had blood spots in 1.97 percent of their eggs and the slatted-floor birds produced eggs that contained blood in 1.92 percent of their eggs. A total of 6620 eggs were examined with 3050 of these from the litter- floor group, 2810 from the slatted—floor pen and 760 from cages. These were the same eggs used for making Haugh unit, shell thickness and weight comparisons. The total number 73 and Size of the various blood spots is shown in Table 37. All spots, both blood and meat, were found in the largest percentage in cage produced eggs. The respective percentages for birds in cages, on a litter floor and on a slatted floor were 13.29, 12.30 and 10.89 percent. The number of meat spots, classified according to small, medium and large, are listed in Table 37. A t-test was used for making a statistical comparison between management methods relative to the incidences of blood and meat spots. No statistical differences were evident when all spots were considered (Table 38). How— ever, when just blood spots were taken into account a statistical difference at the five—percent level was ob- served between the slatted-floor birds and those in cages (Table 39). Pen temperatures. Average monthly temperatures are shown in Table 40. In general, these temperature readings are higher than they were the previous year. The lowest average monthly temperature during the 1960-1961 laying season was 46.900 F. This was recorded in the slatted-floor pen during March. Readings in the litter—floor pen and cage room averaged 48.230 F. and 48.100 F., respectively during this same time. 74 Highest monthly temperatures were recorded at 4:00 p.m. in the month of July. The average readings were 82.450 F. in the litter-floor pen, 81.900 F. in the slatted—floor pen and 79.740 F. in the cage room. 5 7 th.o¢ hmo.NH 0mm.NN momm ¢m¢.ov MBNN mfim.HH meow H¢H.¢N mwm.hm 50mm ovm.OH hHwH HNM.N$ .HB 50mm hvma wfiom Nev mmmm mam mbma NNH homa thm mav mmNH on ommH MHdh mobm OHOH MNNN mfim mmmm haw mNOH mmH ¢ONN m¢¢m mom mom @MH H¢ON wand Homm .hooa hflmm how Noav oav ofloa mmH N¢¢N wmhm mdw mhm NMH @mNN hmz Hmmm HhNH MNON mom mmmm mam NNMH 55H whom Hmhm NNM fimHH ova mfiam .Hmfl HHmm gooa homm ofio mNmM HmN NHOH mmH oth omwm mam mmm hmH wovm .HMS mmmm 0mm mhmH mom Noom Hma mom and homH mmmm . Had mob mNH oooa .Qmm mmmm fimNH moom mam mamm mNH ¢hOH 55H vaH om¢m ¢MH HMHH va Hmom .GMb Homa m¢~¢ NQMH mmNN mmo whmm om omNH wow oowm ommm v0 ONHH MBA MBHN .an ofiav mNHH 55mm V¢w MHV¢ mv HmHH mum mmmN mmmm om H¢m HAN Hmmm .>OZ 00mm ¢MNH omHN va NON¢ ON N¢MH mam Nmmm o¢wm mm vONH Nam omNN .DUO Hmoa mom vooa vna waH m mmg moa VNNH mama m mom mom m¢HH .ummm coma a a u a m 3 ,3 rm m w}... .3 .3 .. .I is. .3 a I s I s I I s e 1 a I s e 1 a as D D. D D. a a _ _ mmmm mmmo mmmm HOOHMIHmuuHA ammo HOOHMIUwuumam u““““ulI\ Hmmaloomallmomm mo muwnesc Hmuou CH coauoswoum mam manucoz .ma manna 76 Table 20. Weekly egg production in percent based on total number of birds-~1960-l96l Percent egg production Dates weeks Slatted Litter Ca es floor floor 9 September, 1960: 1—7 1 11.71 9.64 9.71 8—14 2 21.79 21.57 20.00 15-21 3 37.93 36.57 30.86 22-28 4 45.86 48.14 40.64 29-5 5 51.21 55.79 53.93 October: 6-12 6 62.36 61.86 58.86 13-19 7 64.00 70.86 65.71 20-26 8 65.86 73.07 66.79 27—2 9 61.21 76.57 68.57 Nbvember: 3-9 10 63.07 71.93 69.00 10-16 11 57.86 73.43 70.07 17-23 12 57.29 74.21 67.36 24—30 13 60.93 74.00 70.14 December: 1-7 14 61.43 71.71 71.57 8—14 15 59.79 72.29 70.43 15—21 16 55.07 61.29 68.50 22—28 17 52.71 55.86 64.71 29—4 18 54.21 54.36 65.00 January, 1961: 5-11 19 57.64 52.79 63.57 12-18 20 54.57 54.57 63.50 19—25 21 57.00 54.14‘ 63.50 26—1 22 52.50 51.00 64.07 February: 2—8 23 44.50 50.00 62.79 9-15 24 42.07 52.71 63.21 16-22 25 49.43 55.43 63.43 23—1 26 58.07 61.43 62.50 77 Table 20. Continued Percent egg production Dates weeks Slatted Litter Ca es floor floor 9 March: 2-8 27 62.21 64.29 64.79 9—15 28 62.50 66.00 64.29 16—22 29 62.36 63.86 61.57 23-29 30 62.07 61.79 62.14 30—5 31 62.64 61.07 62.64 April: 6-12 32 62.50 63.36 63.93 13-19 33 64.50 62.71 65.50 20-26 34 64.21 67.79 65.21 27-3 35 62.21 68.07 65.93 May: 4-10 36 61.50 67.93 65.29 11-17 37 61.07 65.93 61.79 18-24 38 60.14 65.14 62.36 25—31 39 60.93 64.86 63.93 June: l-7 40 57.79 66.14 65.93 8-14 41 56.57 62.64 62.86 15—21 42 57.00 64.50 62.79 22-28 43 57.86 63.07 59.93 29—5 44 57.86 61.29 61.50 July: 6-12 45 59.57 61.57 63.50 13-19 46 56.43 62.64 62.29 20-26 47 55.36 63.57 62.07 27—31 48 60.20 62.60 62.10 Average 55.97 60.53 61.05 ‘.‘;°- . . 7‘ fl- .' .KJI: ‘ .i .02.. . :hw._ 78 Table 21. weekly egg production in percent for single and two-bird cages based on total number of birds and hen—day basis-—1960—1961 Percent egg production Dates Weeks Total birds Hen-day basis Single Two Single Two birds birds birds birds 1960 Sept. * 1-7 1 1.88 14.38 1.88 14.38 8—14 2 9.50 23.50 9.50 23.50 15—21 3 22.00 33.25 22.00 33.25 22—28 4 36.00 42.50 36.00 42.50 29-5 5 45.50 58.00 45.50 58.00 Oct. 6-12 6 52.50 62.13 52.50 62.19 13—19 7 65.50 65.63 65.50 65.31 20-26 8 58.00 68.00 58.00 67.48 27—2 9 67.50 69.00 67.50 69.35 Nov. 3-9 10 68.50 68.00 68.50 68.57 10—16 11 70.00 67.88 70.00 68.44 17-23 12 75.00 65.38 75.00 65.58 24—30 13 78.50 69.13 78.50 68.85 Dec. 1-7 14 76.50 70.00 76.50 70.66 8-14 15 79.50 68.75 79.50 69.74 15-21 16 71.50 66.75 71.50 67.50 *22—28 17 70.63 62.97 70.63 63.29 *29—4 18 71.88 64.69 71.88 64.70 1961 Jan. 5—11 19 73.00 60.63 73.00 60.95 12—18 20 72.00 60.88 72.00 61.76 19—25 21 68.50 60.63 68.50 61.62 26—1 22 70.00 63.00 70.00 64.59 Feb. 2—8 23 69.50 60.88 69.54 61.35 9—15 24 71.50 61.38 70.77 62.13 16-22 25 71.50 62.50 71.28 63.40 23-1 26 71.00 61.50 71.28 62.64 79 Table 21. Continued Percent egg production IDates weeks Total birds Hen-day basis Single TWO Single Two birds birds birds birds Inafch 2-8 27 73.00 63.25 72.82 63.33 9-15 28 74.00 61.75 74.36 62.08 16-22 29 65.00 60.75 65.13 61.17 23—29 30 67.50 61.25 68.21 60.79 30-5 31 67.50 61.88 67.69 62.57 April 6-12 32 74.50 62. 50 74.87 62.61 13—19 33 71.50 63.13 72.31 64.09 20—26 34 69.00 64.50 69.23 66.72 27-3 35 72.50 66.00 72.82 66.30 May 4—10 36 66.50 64.38 66.67 64.53 11—17 37 62.00 61.25 61.54 62.50 18-24 38 67.00 62.00 67.18 62.26 25-31 39 63.50 65.13 64.10 66.35 .Iune 1-7 40 68.50 66.25 68.21 67.46 8-14 41 62.00 62.25 61.54 62.90 15-21 42 55.50 63.25 55.90 64.03 22-28 43 59.00 60.88 58.46 62.26 *29-5 44 58.75 64.06 59.62 64.52 .July 6—12 45 56.00 65.25 56.92 66.45 13—19 46 59.00 63.00 60.10 63.77 20—26 47 58.00 63.13 59.47 63.44 **27-31 48 62.50 64.38 65.49 67.13 Average 63.13 60.99 63.26 61.22 * 4—day week ** 3—day week -.' C ‘l.l‘l Ill zr'lill ) . ,’.. ..f .I 4!" . 80 Table 22. Analysis of variance and studentized—range test on egg production during the 1960-1961 laying season Source of . . S.S. D.F. M.S. F ratio variation Pens 5,447.15 2 2723.58 3.49* Error 256,508.09 329 779.66 Total 261,955.24 331 * Significant at five-percent level Studentized—range testl 137.81 143.19 150.68 I I l I l I Slatted Litter Cages floor floor One-percent level: Cages > slatted floor 1Any two means not overscored by the same line are signifi— cantly different, and any two lots overscored by the same line are not significantly different. 81 Table 23. Total number of deaths by months--1960-l96l Numbers Dates Slatted Litter Cages floor floor September, 1960 1 1 0 October 2 2 3 November 1 3 1 December 2 4 3 January, 1961 11 4 0 February 5 4 3 March 4* 5 4 April 5 4* 3 May 2* l 2 June 6 6* 2 July 6 3 6* Total 45 37 27 * Total includes one replacement bird. 82 Table 24. Causes of mortality during the 1960-1961 laying season Numbers cause Slatted Litter Cages floor floor Visceral lymphomatosis 6 6 2 Prolapses and/or pickouts 6 3 5 Peritonitis 3 6 4 Hepatitis 4 2 l Nephritis 2 l 2 Chronic respiratory disease 1 3 - Impacted oviduct 2 2 — Tracheitis 2 1 - Ascariasis 1 l - Air sac infection 1 l - Catarrhal enteritis 1 - - Erythrol lymphomatosis - - l Tumors _ _ 1 Enteritis 1 - — Undetermined 15 ll 11 Total 45 37 27 Table 25. 83 A t—test comparison between the various pens relative to mortality during 1960-1961 SLATTED FLOOR and LITTER FLOOR 0.2250 - 0.1850 t = 0.04032 0.04000 0.04032 t = 0.99 N.S. LITTER FLOOR and CAGES = 0.1850 — 0.1350 0.03658 = 0.05000 0.03658 ‘1' II 1.37 N.S. SLATTED FLOOR and CAGES 0.2250 — 0.1350 0.03815 0.09000 0.03815 t = 2.36* *Significant at five— percent level LITTER FLOOR and SINGLE-BIRD CAGES = 0.1850 - 0.0750 0.04988 = 0.11000 0.04988 t = 2.21* SLATTED FLOOR and SINGLE-BIRD CAGES t = 0.2250 - 0.0750 0.05105 = 0.15000 0.05105 t = 2.94** SINGLE-BIRD CAGES and TWO-BIRD CAGES t = 0.1500 — 0.0750 0.05031 = 0.0750 0.05031 t = 1.49 N.S. **Significant at one-percent level 84 Table 26. Analysis of variance and studentized-range test on initial weights of pullets as measured on September 1, 1960 Source of . . S.S. D.F. M.S. F ratio variation Pens 3.71 2 1.86 14.3 ** Error 78.99 597 0.13 Total 82.70 599 ** Significant at one-percent level Studentized-range testl 3.19 3.26 3.38 l I I l l l Litter Cages Slatted floor floor One-percent level: Slatted floor > cages, litter floor Any two means not overscored by the same line are signifi- cantly different, and any two lots overscored by the same line are not significantly different. 2..-}- 85 Table 27. Comparison between initial weights of pullets on September 1, 1960 using the t—test--l960- 1961 SLATTED FLOOR and LITTER FLOOR 3.13—8; _ 3019 t: ‘V 0.0007475 + 0.0006111 0.19 V 0.001358 0.19 0.0368 t = 5.16** LITTER FLOOR and CAGES 3.25 - 3.19 .t = 1/ 0.0006111 + 0.0007563 0.06 V 0.001367 = 0.06 0.0370 t 1.62 N.S. SLATTED FLOOR and CAGES t = 3.38 - 3.25 “V 0.0007475 + 0.0007563 0.13 V 0.001504 = 0.13 0.0388 t = 3.35** **Significant at one-percent level ..8- 86 Table 28. Analysis of variance and studentized-range test on final weights of birds as measured on August 1, 1961 S°u¥ce.°f S.S. D.F. M.S. F ratio variation Pens 23.17 2 11.59 27.60 ** Error 206.56 493 0.42 Total 229.73 495 ** Significant at one—percent level Studentized-range testl 3.98 4.32 4.49 L I I I I I Litter slatted Cages floor floor Five-percent level: Cages.) slatted floor One—percent level: Cages > slatted floor Any two means not overscored by the same line are signifi— cantly different, and any two lots overscored by the same line are not significantly different. 87 Table 29. Monthly and yearly feed consumption in pounds—- 1960-1961 Pounds of feed Dates Slatted Litter Cages floor floor September, 1960 1125 1148 1214 October 1550 1400 1450 November 1450 1500 1550 December 1550 1500 1600 January, 1961 1600 1350 1650 February 1500 1450 1450 March 1800 1550 1800 April 1800 1750 1800 May 1650 1500 1550 June 1500 1400 1500 July 1454 1247 1372 Total 16,979 15,795 16,936 Table 30. Average egg size in grams as measured 3- consecutive days monthly during a lO-month period-—l960—196l Average egg size (grams) Dates Slatted Litter Cages floor floor October 17 (1960) 53.42 50.49 51.21 18 53.26 50.13 52.42 19 52.62 51.02 51.63 Average 53.07 50.55 51.79 Nbvember 14 55.28 53.90 56.10 15 55.81 53.83 56.47 16 55.40 54.03 57.02 Average 55.50 53.92 56.52 December 19 58.15 56.24 60.20 20 57.14 56.01 60.45 21 58.08 55.49 59.81 Average 57.79 55.93 60.20 January 16 (1961) 60.27 57.23 61.20 17 59.33 57.89 61.90 18 58.81 57.63 61.73 Average 59.47 57.58 61.60 February 13 60.47 59.02 61.25 14 60.11 58.44 62.00 . 15 59.84 59.40 62.80 Average 60.10 58.95 62.06 March 20 62.31 61.01 63.96 21 62.45 60.19 63.48 22 61.66 60.36 64.26 Average 62.14 60.52 63.94 April 17 62.98 61.13 64.83 18 63.54 60.77 64.16 19 63.53 60.99 64.17 Average 63.36 60.96 64.35 89 Table 30. Continued Average egg size (grams) Dates Slatted Litter Ca es floor floor g May 15 61.82 60.44 63.34 16 61.94 60.69 64.46 17 62.07 60.21 64.50 Average 61.95 60.44 64.12 June 19 62.56 60.07 63.05 20 62.87 59.81 64.58 21 62.75 60.20 63.88 Average 62.72 60.03 63.85 July 24 61.46 58.89 62.69 25 60.47 59.09 62.39 26 62.12 60.06 62-71 Average 61.40 59.34 62.60 Grand average 59.65 57.44 61.02 Table 31. Composite distribution of egg sizes in percen— tages according to U.S.D.A. Standards for Con- sumer Grades--l960-l961 9O Percent WEight Classes Slatted Litter Cages floor floor Jumbo 3.17 1.61 1.32 Extra Large 20.71 11.93 33.68 Large 45.34 41.87 44.21 Medium 26.98 35.48 18.03 Small 3.77 8.72 2.50 Peewee 0.04 0.39 0.26 91 A t-test analysis comparing egg size as measured 3-consecutive days monthly during a 10—month period--1960-1961 SLATTED FLOOR and LITTER FLOOR 59.76 — 57.72 'V 0.01140 + 0.01278 t: m 0.1555 t = 13.12** LITTER FLOOR and CAGES 61.06 — 57.72 'V 0.03859 + 0.01278 t: 3.3400 0.2267 t = 14.73** SLATTED FLOOR and CAGES 61.06 - 59.76 t 1V 0.03859 + 0.01140 1.3000 = ______ 0.2236 t = 5.81** ** Significant at one—percent level Table 33. Average Haugh unit scores for each date and month during the 1960—1961 laying season Average Haugh unit score Dates Slatted Litter Cages floor floor October 17 (1960) 83.59 86.70 89.05 18 85.51 86.98 90.80 19 86.89 86.71 88.50 Average 85.43 86.80 89.44 November 14 82.24 83.45 82.31 15 81.30 81.18 81.24 16 84.31 81.17 81.96 Average 82.69 81.93 81.84 December 19 82.37 84.40 81.74 20 85.17 83.45 81.76 21 80.66 83.18 81.67 Average 82.73 83.71 81.73 January 16 (1961) 80.17 80.13 79.80 17 80.65 80.88 81.52 18 78.08 82.96 78.84 Average 79.70 81.33 79.94 February 13 80.47 79.00 79.42 14 73.38 78.19 74.08 15 75.04 75.51 77.03 Average 75.91 77.55 76.89 March 20 80.74 77.19 76.82 21 76.72 80.07 75.80 22 76.34 78.54 76.56 Average 77.94 78.61 76.45 April 17 78.21 77.69 77.17 18 78.24 79.83 76.48 19 77.51 78.09 75.00 Average 77.99 78.52 76.18 Table 33. Continued Average Haugh unit score Dates Slatted Litter Ca es floor floor g May 15 74.03 74.62 71.77 16 73.39 75.49 73.58 17 73.65 74.56 76.14 Average 73.68 74.88 73.81 June 19 72.66 75.26 70.77 20 74.42 75.06 74.00 21 73.68 74.34 73.06 Average 73.57 74.90 72.61 July 24 75.33 76.60 73.50 25 75.23 76.15 75.55 26 69.84 72.23 75.24 Average 73.27 75.04 74.72 Grand average 78.53 79.72 78.56 94 Table 34. Analysis of variance for a random selection of Haugh unit scores measured during the 1960-1961 laying season Source of variation S.S. D.F. M.S. F ratio Pens 99.18 2 49.59 0.73 N.S. Seasons 3161.45 2 1580.73 23.19 ** Interaction 154.42 4 38.61 Error 6865.02 99 69.34 New error 7019.44 103 68.15 Total 10280.07 107 ** Significant at one—percent level I n 0.. n _ a Table 35. Average shell thickness in fractions of an inch as measured during the 1960—1961 laying season Shell thickness (x0.001 inches) Dates slatted Litter Ca es floor floor 9 October 17 (1960) 14.07 14.18 14.87 18 14.45 14.40 14.74 19 14.43 14.72 14.54 Average 14.33 14.43 14.69 November 14 14.17 14.32 14.76 15 14.20 14.14 15.17 16 13.85 14.50 14.88 Average 14.06 14.32 14.94 December 19 14.18 13.91 14.15 20 13.81 13.45 13.95 21 13.98 13.35 13.79 Average 13.99 13.59 13.98 January 16 (1961) 13.75 13.57 14.17 17 13.70 13.53 13.82 18 13.80 13.37 14.31 Average 13.75 13.49 14.12 February 13 14.07 13.68 14.00 14 14.18 13.64 13.98 15 13.89 13.77 14.25 Average 14.04 13.70 14.09 March 20 13.87 13.40 14.20 21 13.85 13.67 14.18 22 13.83 13.43 14.26 Average 13.85 13.50 14.21 .April 17 14.19 13.83 14.35 18 14.05 13.72 14.12 19 13.81 13.73 13.81 Average 14.02 13.76 14.08 I‘ll! '1 [III Ill. ’1’! l1.’ -M,“ .. I. I . . I. . I. . . :4 2.. a KUI’HWVVIII I. 2‘ III .7 III. .’ .0- II. II - Table 35. Continued Shell thickness (x0.001 inches) Dates Slatted Litter Ca e floor floor 9 5 May 15 13.29 13.03 13.55 16 13.16 13.19 13.63 17 13.74 13.24 13.95 Average 13.40 13.16 13.71 June 19 13.15 12.97 13.14 20 13.51 13.11 13.79 21 13.39 13.16 13.19 Average 13.34 13.08 13.40 July 24 13.09 12.82 13.06 25 12.96 12.81 13.14 26 13.22 12.83 13.64 Average 13.09 12.82 13.27 Grand average 13.80 13.64 14.08 97 Table 36. Analysis of variance and studentized-range test for a random selection of egg shell thick- nesses measured during the 1960—1961 laying season S°u?ce.°f S.S. D.F. M.S. F ratio variation Pens 7.40 2 3.70 3.43* Seasons 15.59 2 7.80 7.22** Interaction 7.91 4 1.98 Error 103.31 99 1.04 New error 111.22 103 1.08 Total 134.21 107 *Significant at five-percent level **Significant at one—percent level Studentized-range testl 13.58 14.14 1 I I I Slatted floor Cages Litter floor One-percent level: Cages > slatted floor, litter floor 1 . Any two means not overscored by the same line are signifi— cantly different, and any two lots overscored by the same line are not significantly different. 98 Table 37. Number and size of blood and meat spots detected in broken-out eggs for 3-consecutive days monthly during a lO-month period--1960-1961 . Number Type and Size Of SPOtS Slatted Litter Cages floor floor Blood spots: 1 Large 23 16 9 Medium2 . 11 17 7 Small3 20 27 9 Total 54 60 25 Meat spots: 1 \ Large 62 80 9 Medium2 96 117 31 Small3 94 118 36 Total 252 315 76 Grand total: 306 375 101 1Over 1/8th of an inch 2Between 1/16th and 1/8th of an inch 3Less than 1/16th of an inch 99 Table 38. A t-test analysis of all blood and meat spots detected in broken-out eggs-—1960-1961 SLATTED FLOOR and LITTER FLOOR 0.1230 - 0.1089 t=-—-—-—-_ 0.00836 0.01410 0.00836 t = 1.69 N.S. LITTER FLOOR and CAGES = 0.1329 - 0.1230 0.01367 = 0.00990 0.01367 t = 0.72 N.S. SLATTED FLOOR and CAGES t = 0.1329 - 0.1089 0.01364 0.0240 0.01364 t = 1.76 N.S. 100 Table 39. A t-test analysis of all blood spots detected in broken—out eggs-—l960—l96l SLATTED FLOOR and LITTER FLOOR _ 0.0197 — 0.0192 0.00361 0.0005 0.00361 t = 0.14 N.S. LITTER FLOOR and CAGES = 0.0329 - 0.0197 0.00694 = 0.0132 0.00694 t = 1.90 N.S. SLATTED FLOOR and CAGES t = 0.0329 - 0.0192 0.00697 0.0137 0.00697 t = 1.97* *Significant at five—percent level 101 Table 40. Average monthly pen temperatures as recorded in degrees Fahrenheit daily at 8:00 a.m. and 4:00 Slatted floor Litter floor Cages Dates 8' é :3 6' 6' 6' m m m m m m o o o o o o o o o o o o 5 5 m J m ¢ September,1960 64.93 72.72 65.93 75.97‘ 64.50 74.34 October 56.84 65.23 57.81 66.48 54.35 62.77 November 54.33 57.70 54.57 57.73 55.80 57.10 December 50.77 51.03 51.42 51.71 52.74 52.65 January 1961 51.61 52.32 53.52 54.32 52.87 50.39 February 47.11 51.04 48.93 52.15 47.86 50.93 March 46.90 55.45 48.23 56.94 48.10 55.61 April 49.90 57.50 51.47 60.47 50.53 59.07 May 57.48 72.42 58.90 72.81 57.03 68.42 June 65.43 78.33 67.47 79.57 65.10 76.37 July 71.19 81.90 72.45 82.45 70.58 79.74 ._mm_lomm_ IImOOJu. mwkkj 02¢. ”50...“. owkbjm < 20 924 mwom ...zwomwa Z_ 20....0300md 00m .m manor. mxww? gmvevwgovmnwmcm «nomom oNvNNNON m. w. .v. N_ o. m w v N . .-o. ION d 896 2.5.9: , .. a muo>._. oz< mqozfi Z. mama mom m_w<0IzwI zo omwm hzwode z. Zorrozoomn. 06m .w umber. mxwu? $$¢¢Nvo¢mnmanmmOnmeN¢NNNON a.m. S N_o_ m w v N [p p p n p - n u n p p P . n p n n u n q n a a u - - . a. u . - u - q q u a a 104 muo cages, litter floor Cages > litter floor 136 Appendix 2. Continued DECEMBER: 5°“Fce.°f s.s. D.F. M.S. F ratio variation Pens 1319.31 2 659.66 43.60** Error 10137.22 670 15.13 Total 11456.53 672 **Significant at one—percent level Studentized—range test2 55.93 57.79 60.20 I 1 I Litter Slatted Cages floor floor One-percent level: Cages > slatted floor, litter floor Slatted floor > litter floor Appendix 2. Continued FEBRUARY, 1961: 137 Source of . . S.S. D.F. M.S. F ratio variation Pens 621.81 2 310.91 l7.48** Error 9911.67 557 17.79 Total 10533.48 559 **Significant at one—percent level Studentized—range test2 58.95 60.10 62.06 I I I I l 1 Litter Slatted Cages floor floor Five—percent level: Slatted floor > litter floor One-percent level: Cages > slatted floor, litter floor Appendix 2. Continued APRIL: 138 Source of . . S.S. D.F. M.S. F ratio variation Pens 1203.74 2 601.87 27.52** Error 14978.00 685 21.87 Total 16181.74 687 **Significant at one—percent level 2 Studentized-range test 60.96 63.36 64.35 I l 1 I T "r Litter slatted Cages floor floor Five-percent level: Cages > slatted floor One-percent level: Cages > litter floor Slatted floor > litter floor 139 Appendix 2. Continued JUNE: Source of . . S.S. D.F. M.S. F ratio variation Pens 1349.46 2 674.73 27.42** Error 15107.80 614 24.61 Total 16457.26 616 **Significant at one-percent level Studentized-range test2 60.03 62.72 63.85 I l l I I I Litter Slatted Cages floor floor Five-percent level: Cages > slatted floor One-percent level: Cages > litter floor Slatted floor > litter floor 2Any two means not overscored by the same line are signifi- cantly different, and any two lots overscored by the same line are not significantly different. Appendix 3. OCTOBER, 1960 140 Analysis of variance and studentized-range test on albumen quality (Haugh scores) as computed on alternate months during the 1960— 1961 laying season Source of . . S.S. D.F. M.S. F ratio variation Pens 1016.35 2 508.18 10.86** Error 36157.62 773 46.78 Total 37173.97 775 **Significant at one—percent level Studentized-range test3 85.43 86.80 89.44 1111, J l I I 1 Slatted Litter Cages floor floor Five-percent level: Litter floor > slatted floor One-percent level: Cages > litter floor, slatted floor 141 Appendix 3. Continued DECEMBER: Source of . . S.S. D.F. M.S. F ratio variation Pens 303.76 2 151.88 3.40* Error 29885.42 670 44.61 Total 30189.18 672 *Significant at five-percent level Studentized—range test3 81.73 82.73 83.71 I 1, 11 I I I Cages Slatted Litter floor floor One—percent level: Litter floor > cages 142 Appendix 3. Continued FEBRUARY: 1961 Source of . . S.S. D.F. M.S. F ratio variation Pens 318.95 2 159.48 2.27 N.S. Error 39129.11 557 70.25 Total 39448.06 559 APRIL: sou?°e.°f s.s. D.F. M.S. F ratio variation Pens 345.22 2 172.61 2.98 N.S. Error 39704.57 685 57.96 Total 40049.79 687 JUNE: soche.°f s.s. D.F. M.S. F ratio variation Pens 389.31 2 194.66 2.96 N.S. Error 40404.41 614 65.81 Total 40793.72 616 3 . . . . Any two means not overscored by the same line are Signifi- cantly different, and any two lots overscored by the same line are not significantly different. Appendix 4. 143 Analysis of variance and studentized—range test on shell thickness as computed on alternate months during the 1960-1961 laying season OCTOBER, 1960: Source of . . S.S. D.F. M.S. F ratio variation F Pens 8.17 2 4.09 3.03* I 1 Error 1047.05 773 1.35 E Total 1055.22 775 *Significant at five—percent level Studentized—range test4 14.33 14.43 14.69 11, J l l T— I Slatted Litter Cages floor floor Five-percent level: Cages > litter floor One-percent level: Cages > slatted floor 144 Appendix 4. Continued DECEMBER: soche.°f s.s. D.F. M.S. F ratio variation Pens 26.59 2 13.30 7.23** Error 1233.86 670 1.84 Total 1260.45 672 **Significant at one—percent level Studentized-range test4 13.59 13.98 13.99 I I 1J1 l I l Litter Cages Slatted floor floor One-percent level: slatted floor, cages > litter floor Appendix 4. Continued FEBRUARY: 1961 145 Source of . . S.S. D.F. M.S. F ratio variation Pens 17.74 2 8.87 6.77** Error 730.45 557 1.31 Total 748.19 559 **Significant at one-percent level Studentized-range test4 13.70 14.04 14.09 J I l l T F Litter Slatted Cage floor floor One—percent level: Slatted floor, cages > litter floor Appendix 4. Continued APRIL: 146 Source of . . S.S. D.F. M.S. F ratio variation Pens 12.36 2 6.18 4.38* Error 964.41 685 1.41 Total 976.77 687 *Significant at five—percent level Studentized—range test4 13.76 14.02 14.08 J I l I I I Litter slatted Cages floor floor Five—percent level: Slatted floor > litter floor One—percent level: Cages > litter floor Appendix 4.. Continued JUNE: Source of . . S.S. D.F. M.S. F ratio variation Pens 12.00 2 6.00 4.76** Error 776.32 614 1.26 Total 788.32 616 **Significant at one—percent level Studentized-range test4 13.08 13.34 13.40 11 I I l l l Litter Slatted Cages floor floor Five-percent level: Slatted floor > litter floor One—percent level: Cages > litter floor 4 . . . Any two means not overscored by the same line are Slgnl- ficantly different, and any two lots overscored by the same line are not significantly different. Appendix 5. 148 Equipment depreciation cost per dozen eggs produced during the 1959-1960 laying season slatted Floor: 1. 2. 3. 4. Litter l. 2. 3. 4. 5. Cages: Slats and materials - $125.73 @ 5 yrs. Waterers - $8.73 @ 8 yrs. Feeders - $53.20 @ 8 yrs. Nests - $36.00 @ 8 yrs. TOTAL Cost per dozen (1571.2 doz.) Floor: Litter — 22 bales @ $25 per ton Waterers — $8.73 @ 8 yrs. Feeders - $53.20 @ 8 yrs. Nests - $36.00 @ 8 yrs. Roosts - $33.40 @ 8 yrs. TOTAL Cost per dozen (1792.2 doz.) Cages and materials - $247.20 @ 8 yrs. TOTAL Cost per dozen (1780.8 doz.) $25.15 = 1.09 6.65 = 4.50 $37.39 $0.024 = $19.25 = 1.09 = 6.65 = 4.50 = 4.18 $35.67 - $0.020 = $30.90 $30.90 = $0.017 - ‘ “I am USE 0m flu... I.,...I MICIITIGWIISIITI WI lu WIIVIIEIIIISI'IITIIYIIII'IIBIMIWES 3 1293 (13047l 0771