HY SlC AL iN CERTAIN P 603 N8 C ERlST‘CS OF E ROM PUREBRED CROSS BREE) PULLBTS Thesis for tho Dean. of M. S. N STATE COLLEGE. M‘CH‘GA William Bevefly Robinson 194‘ .1,th 57'“. f: .1. ~ ' ' 3'3? 2 . '19" FVSLJ L" ‘znfi "Zl‘";%.’.l’.2".:"'.f .15; "f1; 5., . w ‘i t" * l I. ,i “-5 J! ‘ ’1, .m’fi 'i¢._ ”éIWM’EE‘“ a 'VARIATIONS IN CERTAIN PHYSICAL CHARACTERISTICS OF EGGS FROM PUREBRED AND CROSS BRED PULLETS By William Beverly;§g§inson A THESIS Smeitted to the Graduate School of Michigan State College of Agriculture and Applied Science in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE Department of Poultry Husbandry 1941 ACKNOWLEDGEMENT The author expresses sincere appreciation to the following persons for their aid: Dr. E. W. Henderson, Assistant Professor of Poultry Husbandry; J. A. Davidson, Associate Professor; and other members of the Poultry Husbandry staff. Appreciation is also due Dr. W. D. Eaten, Associate Professor of Mathematics for aid in making statis- tical computations. 13%238 TABLE OF CONTENTS Chapter I. INTRODUCTION . . . . . . II. REVIEW OF LITERATURE . . III. EXPERII‘flENI'AL . . . . . . Object . . Procedure. . . Physical Characteristics Shell Texture. Contour . . . Shell Porosity Yolk Movement Egg Weight . . Analysis of Data . Results . . . IV. DISCUSSION . . . . . . . V. CONCLUSIONS . . . . . . VI. SUMMARY . . . . . . . VII. LITERATURE CITED . . . . APPENDIX . . . . . . . Page 10 10 11 20 23 25 27 I. INTRODUCTION Present Michigan egg grading standards are based in part on some of the following criteria: external shell texture, contour, porosity, yolk movement and egg weight. In.the past it has generally been a common belief that environmental conditions were entirely responsible for these characters; but recently considerable evidence has been found that supports the Opinion that they are hereditary. The mode of inheritance of many of the foregoing characters is not known, nor are uniform methods of measuring certain criteria established. Whether cross breeding or so called pure breeding are best as methods for establishing the criteria mentioned is not known either. JI-n‘viewof the fact that cross breeding seems advantageous in the case of some quantative characters, it seems desirable to measure the relative performance of cross bred and purebred progeny with respect to some of the "egg quality" characters. 2. II. REVIEW OF LITERATURE A review of the literature reveals some of the following cri- , teria for measuring quality of eggs: texture; contour; porosity; yolk movement and egg weight. Some correlation of these criteria with practical Egg Grading Standards of the U. S. Department of Agriculture and Michigan Department of Agriculture is generally assumed, although they are not well established. Texture Opinions of the significance of texture differs among research workers. Some define it as the Shell's structural makeup, while others define it on the basis of external smoothness. Hays (12) used a system of grading shell texture in which he separated eggs into four groups on the variability of the external shell appear- ance. This method consists of classifying eggs as rough, ridged, sandy and normal. NOrmal eggs were considered as being smooth and free of any conspicuous ridges. Ridged eggs may or may not show sandy spots. Rough eggs exhibit mineral spots. As to the relative variability in.a homogenous group of pul- let eggs, Fronda and Andrews (8) presented data showing that medium and good external shell texture represents 40 to 77 percent of all eggs laid throughout the year. Contour Contour is a classification term used by Henderson (15) to describe ridges appearing on the shell. Closely related to contour is a condition.known as wrinkled shell. Asmundson (4) noted this condition after operating on the hen's oviduct. Eggs laid by certain 5. hens after the isthmus was torn longitudinally and the tear closed with cat gut sutures had shells which were characteristically wrinkled. This substantiated work done by Pearl and Surface (14). Curtis (7) showed that individual hen's eggs are quite var- iable among themselves, but that they resemble each other more closely than eggs of a random sample from the same strain. Eggs of the in- dividual tend to be either uniform or variable in all characters while certain others may show a deviation in certain characters and uniformity in others. Porosity Porosity is a term that seems to be used to describe at least two characteristics of the egg shell. One condition described by Perry (15) is "apparent porosity" distinguished when an egg is -held before the candle and is characterized by variable transmission of light through the shell resulting in translucent Spots. This cone dition is popularly supposed to indicate holes or pores in the shell or at least thin spots. Almquist, Holst and Lorenz (5) cast doubt on this assumption. Perry (15) did not presume any relationship but justified his use of the term "apparent porosity” by stating that it is a distinct characteristic and therefore worthy of study. True porosity is not visible by the unaided eye and therefore it is not used in commercial grading of eggs. The criterion used in this work was ”apparent porosity". It does not seem to be as transient in nat- ure as Holst, Almquist, and Lorenz conclude. It has been generally accepted that breaking strength of the egg's shell is a true measure of its porosity and that highly porous shell have a low breaking point. 4. Van Wagenen and Wilgus (18) observed a weaker condition in shells laid by Barred Rocks than in those laid by the Single Comb White Leghorn and Rhode Island Red breeds. This work was confirmed by Taylor and Martin (16) who noticed, while conducting a feeding experiment to determine some factors influencing thickness in egg shells, that individual differences in weight of egg shells between hens were great. Even in their control pens, where deficiency feed- ing had existed for six and one-half months, individuals were found to produce heavily shelled eggs, while others were producing rather thin shells. Among their Barred Rocks, which producedquite a number of thin shells, the average percent of shell failed to reach the average for the White Leghorn. The average percent of shell for the Barred Rock was 8.66 as compared to 9.15 for the White Leghorn. This difference was more than six times the probable error and sig- nificant. Yolk Movement Yolk movement is considered an essential criterion in esti- mating the viscosity of the albumen of eggs. Van.Wagenen.and Wilgus (18) studied the relationship between the score of the observed COD? dition of the firm albumen and the candling quality, using 199 eggs. Yolk mobility was scored 1 for very slight mobility to 5 for very freely mobile yolks. In every case a significant correlation was found between the observed condition of the firm albumen, mobility of the yolk, yolk shadow mobility, and the candler's grade. Results indicated that the condition of the firm albumen is closely related to those factors in determining the candling quality of the egg. This work was in contrast to work by Almquist (1) who found no 5. correlation between the quality of firm albumen and apparent mobility of the yolk. He states that "since the yolk spins in a very fluid medium-the inner fluid layer of white-the manner in which the Spin takes place refers to the anchorage of the yolk rather than the con- dition of the white". Van Wagenen.Hall and Wilgus (17) noted that the Rhode Island Reds and Barred Rocks did not differ significantly within the breeds with respect to the percentage of firm albumen. Egg Weight Funk and Kempster (10) reported a wide range of variation in egg weight and that egg weight is not definitely associated with the breed, but with individuals of the strain. In the breeds they worked with, egg weight ranked as follows: Rhode Island Red, Anconas, White Wyandotte, and White Leghorn. Hall (11) published data showing mean egg weight of 57.50 grams for Barred Books; 57.21 grams for White Wyandottes; and 56.75 for Rhode Island Reds. Atwood (5) noted that larger hens had a tendency to lay larger eggs and that these were of an average size for the breeds. Variations in mean egg weights were recorded by Fronda and Clemente (9) with individual weights ranging from 54.78 grams to 58.51 grams in a flock of Los Banos Cantonese fowl. 6. III . EXPERIMENTAL Object The object of this study was to determine the significance of variations in certain physical characters among eggs laid by the F1 pullet progeny of the following matings: Single Comb White Leghorn; Barred Plymouth Rock; Dark Cornish x White Leghorn; Rhode Island Red; and White Cornish x barred Rock. Procedure The method of scoring criteria was similar to that used by Perry (15); but revised and extended by Henderson (15). It consists of grades ranging from one to five. Physical Characteristics Shell Texture In grading shell texture, eggs were segregated into five classes ranging from perfect to very poor and given numerical values. The range of this characteristic is illustrated in Fig. 1. Contour Contour is a term of classification used by Henderson (13) to describe ridges appearing on the surface of the shell structure and any other variation from the normal ellipsodal curvature of the egg. In this study, a normal egg is graded 1; eggs with slightly pronounced ridges 2; and other degrees of variation are scored accordingly up to 5 for the most extreme variants. Fig. 2, is an illustration of the method used in scoring contour. 7. ( U” *7" Fig. 1. Shell texture (Grades 1-5) Fig. 2. Contour (Grades 1-5) 8. Shell Porosity Apparent porosity is a condition visible when an egg is held before a candle. thether apparent porosity indicates actual openings in the shell is a controversial question. No attempt was made to demonstrate a relationship between apparent porosity and true porosity in this work. The condition is simply scored as it appears in degrees ranging from 1 to 5. An example of eggs graded 1 on porosity is illus— trated in Fig. 5. An egg with few "apparent pores" and a good internal shell texture probably will permit light to penetrate to a lesser de- gree than one with more pores. Fig. 5. Porosity (Grade 1) Figs. 4 and 5. illustrates eggs graded 2 and 5 on porosity. It close comparison of the two reveals that Fig. 5 exhibits more and JLarger "pores" than Fig. 4. Fig. 4. Porosity (Grade 2)* Fig. 5. Porosity (Grade 5)* Figs. 6 and 7 are illustrations of types of porosity in which the eggs were graded 4 and 5 respectively. Yolk Movement When determining the quality of the internal contents of eggs, the speed with which the yolk rotates is considered a criteron. In judging eggs in this work, the egg was rotated before the candle and the Speed of the yolk's movement was estimated. It might be conceded that the intensity of the yolk shadow may influence one's estimate of yolk movement, but an experienced cendler can easily distinguish this *Black spots are on the external shell surface and not related to porosity. 10. condition. It is supposed to be indicative of a weak interior struc— ture of the albumen or small percentage of thick albumen. A yolk imbedded in a firm sack of thick albumen was assumed to have very little movement from its center and was graded 1. Easter moving yolks were graded 2 and 3 depending upon their mobility. Those egg yolks which moved freely and rapidly were graded 4 and 5 respectively. r15. 6. Poresity (Grade 4) Fig. 7. Porosity (Grade 5) Egg Height Eggs were weighed on a balance accurate to one-tenth of a gram. Analysis of Date The data were analysed by a method of Analysis of Variance described by Eaten (6). The influence of individual pullets is reduced 11. to unity by determining the mean value for the group of eggs laid by each individual. Results The average scores for all characters observed are given in Table l by breeds. Data treated statistically by an analysis of variance for texture, contour, porosity, yolk, movement and egg weight between cross bred and purebred pullets are presented in Tables 2, 5, 4, 5, and 6. Table 1. AVERAGE SCORES BY BREED FOR THE CHARACTERS STUDIED ANDRE EGGS 0F PUREBRED AND CROSS BRED PULLETS* Characters 1. Yolk Breed Texture Contour Porosity movement heieht Rhode Island Red 2.57 1.89 5.85 2.10 58.72 Barred Plymouth Rock 2.76 2.51 4.04 2.21 55.76 White Cornish x Barred Plymouth 2.54 1.98 5.92 1.87 ' 55.04 Rock S. C. White Leghorn 1.97 1.99 5.98 2.54 55.74 Dark Cornish x Whiteggeghorn 2.15 2.00 4.51 2.50 54.67 *See Appendix Tables 1-5 for average individual scores by breeds. l2. Variations Between Breeds ( The results of the analysis of variance, designed to measure the difference in egg characteristics between purebred and cross bred pullets, are presented in Tables 2—7. The "F" value to reveal signi- ficance between any two means should attain a value of 2.56 at the 5 percent point. If an F value as great, or greater than this is found, one can.assume that a difference does exist between breeds with 95 percent accuracy. Table 2. ANALYS‘S OF VARIANCE OF THE TEXTURE DATA FOR EGGS BETWEEN PUREBRED AND CROSS BRED PULLETS Source of Variance D. F. S. 8. Mean Square F. Total 52 27.57 4 Between breed means 4 5.05 .76 1.49 Within breeds 48 24.54 .51 The analysis of texture variance is presented in.Table 2. The mean square between breed means only exceeds the mean square within breed means by .25 which shows that the difference between breeds is very small. The ratio or F value between means is 1.49. This value is less than the required value for significance by a whole number and certainly insignificant between breeds. 15. .Table 5. AEALYSIS OF VARIANCE OF THE CONTOUR DATA FOR EGGS BET‘GLELN PUBEBRED AND canes BREE mums Source of Variation D. F. S. 8. TT' Mean.Square ‘ F. Total 52 10.78 Between breeds 4 .91 .25 1.11 Within breeds 48 9.87 .21 The analysis of contour variance is presented in.Table 5. All breeds observed show relatively the same degrees of contour deviation as illustrated in the mean square column. The difference between only exceeds the difference within.by a margin of .02 and has an F value of 1.11 as great. Table 4. AKALYSIS OF VARIANCE OF THE POROSITY DATA FOR EGGS BETWEEN PUREBRED AND CROSS BRED PULLETS Source of Variance D. F. S. S. Mean.Square F. Total 52 25.62 Between breed means 4 1.52 .58 .82 Within.breed means 48 22.10 .46 The analysis of variance for the porosity data is given in Table 4. The variance within breeds is greater than the variance between breeds, as explained in the mean square column. The difference is an insignificant value of .82 shown in the F column. 14. Table 5. THE ANALYSIS OF VARIANCE OF THE YOLK MOVEMENT DATA FOR EGGS BETWEEN PUREBRED AND CROSS BRED PULLETS Source of Variance D. F. S. S. Mean Square F. Total 52 11.01 Between breed means 4 1.54 .54 1.66 Within breed means 48 9.67 .24 In Table 5 is given the analysis of variance for the yolk movement data between breeds. There is a difference to be noticed, but this differ- ence is not significant as shown by the ratio of between breeds to within breeds in the table. It is noted that in no case did the F value reach or exceed the given value of F for error point of 5 percent. This indicates that char— acteristics measured are equally variable within breeds and not signifi- cantly important between breeds. It further indicates that in all breeds measured there are possibilities of equal individual potentialities. Table 6. ANALYSIS OF VARIANCE OF EGG WEIGHT DATA AMONG PUREBRLD AND CROSS BRED PULLETS. Source of Variance D. F. S. S. Mean.Square F. Total 52 620.10 Between breed means 4 250.17 57.54 7.08“ Within breed means 48 589.95 8.12 " Highly significant "I" value 15. In computing the analysis of variance of egg weights between the breeds, the average weight of all eggs laid by a pullet was con- sidered to be representative of the individual pullet's production. There is a difference between the means of the representatives of at least two of the groups of pullets comprising the breeds. Therefore 58.72 is significantly greater than all the other mean weights. The mean.weight (55.72 grams) for the Barred Plymouth Rock pullets is also significantly greater than the mean weight (55.04 grams) for the cross bre White Cornish x Barred Rock. Variation Eithin breeds After showing that there is no significant difference in four of the characters measured between purebred and cross bred pullets, it remains to determine the nature of the variables within the breeds observed. From a study of the sums of the squares in the preceeding tables presenting texture, contour, porosity, and yolk movement, it is evident that the sums of squares are greater within in most cases than between - so much so that the difference within is almost equal to the difference between. To determine the nature of this difference five birds were selected from each breed and an analysis of variance was computed for each of these characters. It was found that five birds were just as accurate as all birds would have been and that it was not necessary to use them all to determine this variance. These five birds for each breed gives a fair representative sample of what one might expect from all the birds. In the following tables data that are treated statistically for analyses of variances within breeds are presented in Table 7. Texture scores; in Table 8. contour scores; in Table 9. porosity scores; and in.Table 10. yolk movement scores for all breeds. 16. ’ Table 7. ANALYSES OF VARIANCES FOR TEXTURE OF EGGS PERTAINIHG TO BREEDS 0F POULTRY - SHOWING THE F VALUES. Source of Variance Breed Total Between Pullets _Within Pull ts F D.F. S.S. D.F. 8.8. Var. D.F. 8.5. Var. Value Rhode Island Red 150 142.7 4 57.94 14.49 126 84.76 .67 21.6** S.C. White Leghorn 55 54.84#' 4 4.25 1.06 51 50.61 .99 1.07 y Dark Cornish 1 x i White Leghorn 90 90.62 4 57.66 2.3;: 86 55.54 .62 14.9543; Barred Plymouth 1 Rock 55 121.10 4 26.90 6.75 151 94.2 .71 9.47** 2/ White Corniéfi A x Barred Plymouth Rock 171 155.4 4 56.20 11.24 166 99.39 .60 16.4044 ** Highly significant differences within breeds. 1/ Single comb Hhite Leghorn and Dark Cornish Cross 3/ Barred Plymouth Rock and hhite Cornish Cross l7. Table 8. AKALYSES 0F VARIANCE FOR CONTOUR 0F EGGS PERTAIKING TO BRLFDS 0F POULTRY - ShOhING THE F VALUES. _‘_ Source of Variance Breed Total Between Pullets Vithir Pullets F. D.F. S.S. D.F. ‘§,S. 4ygr. D.F. S.S. Var. value Rhode 1 Island Red 150 80.99 4 4.85 1.22 1:26 76.14 .60 2.01 8.0. White Leghorn» :7, 55 49.95 4 22.29*‘ 5,57 .51,27.64 .54 0.515% 1 Dark Cornish x White Leghorn 90 56.99 4 9.462; 2.57 .86 27.55 .52 7.41** Barred Plymouth Rock 155 95.62 4 2.12 .55 1.51 95.50 .71 .75 a White Cornish x Barred Plymouthi Rock 155 _'§§.84 4 6.71 1.45 1.51 81.15 .54 2.66** ** Highly significant differences within breeds 1/ Single comb White Leghorn and Dark Cornish 3/ Barred Plymouth Rock and White Cornish Table 9. ANALYSES OF VARIANCE-S FOR POROSITY OF EGGS PERTAINING TO BREEDS OF POULTRY — SHORTPE THE F VALUES 18. Source of_Variance Breed Total Between Pullets Within Pullets “ F. D.F. S.S. D.F. 8.5. Var. D.F. 8.8 Var. Value Rhode Island Red 150 127.54 4 75.94 18.49 _126 55.60 .45 45.0054 S.C. ' White - Leghorn 55 97.45 4 64.44 16.11, 51 55.99 1:67 24.04** 1/ Dark Cornish x White Leghorn 90 56.62 4 22.50 5.58 86 54.52 .40 15.95%* Barred Plymouth Rock 155 142.12 4 40.11 10.05 151 102.01 .78 12.6655 _27 Ehite Cornish x Barred Plymouth Rock 155 209.08 4 60.82 40.21 151 48:26 .52 15.55fi5‘ ** Highly significant differences within breeds 1/ Single Comb White Leghorn.and Dark Cornish Cross .g/ Barred Plymouth Rock and “bite Cornish Cross J 19. Table 10. ANALYSES 0F VARIANCES FOR YOLK MOVEMENT OF EGGS PBETAIKING BREEDS 0F POULTRY - SHOWING THE F VALUES Source of Variance Breed Total Between Pullets Within Pullets F D.F. 5.3. D.F. s.s. Var. D.F. s.s. Var. Value Rhode Island Red 150 82.50 4 8.85 2.21 126 75.67 .58 5.81** S.C. White Leghorn 55 51.72 4 10.85 2.71 51 40.87 .80 5.58** 1 Dark Cornisfi/ x White Leghorn 90 ' 85.14 4 10.56 2.65 86 72.64 .84 5.15** Barred Plymouth l Rock 155 102.55 4 4.65 1.16 151 97.88_ .75 1.54 3/ l White Cornish x Barred Plymouth Rock 155 119.59 4 15.90 5.98 151 105:69 .69 5.71fif ** Highly significant differences within breeds ‘1/ Single Comb White Leghorn and Dark Cornish Cross 3/ Barred Plymouth Rock and White Cornish Cross 20. IV. DISCUSSION As to the criteria, texture, contour, porosity yolk movement, and egg weight, it seems apparent that only one criteron (egg weight) varies significantly between the F1’ generation of purebred and cross bred pullets used in this study. From the analyses of variance within the breeds it is clear that all breeds vary significantly in some characters. For egg weight between breeds, a significant value of 7.08 was obtained. This value was significant for two breeds. The Rhode Island egg weight wassuperior to all breed egg weights, while the Barred Rock was superior to the cross bred progeny of White Cornish and Barred Rock. The values of 1.49 for texture, 1.11 for contour, 0.82 for por- osity, and 1.66 for yolk movement were all insignificant between breeds. These values suggest a close relationship among individuals and among breeds of purebred and cross bred pullets. These values further substan- tiate the opinion that all breeds are equally variable for texture, CON? tour (ridges), porosity, and yolk movement. Some breeds may vary in some characters while othersare uniformly variable in all characters, as indicated in the analyses of variances for individual breeds. From the Tables 6—10, analyses of variances within the breeds, it is to be noted that the cross bred progeny of each mating was uni- formly variable in all characters observed, while the purebreds were only variable in certain characters. Data were sufficient to show that intra individual variance is as equal between purebreds as between cross breds. Data were 21. sufficient also, as evidenced in the statistical analyses of individual averages, to indicate that these characters are not associated with any particular breed, but with those individuals within the breed. Fig. 8, illustrates this very effectively. This pullet, No. 5225, _ a Barred Plymouth Rock, invariably laid eggs with an extremely poor shell texture, ridged, odd shaped, and in a highly porous condition; while another pullet, No. 5214, of the same breed laid eggs of better than normal condition, with respect to these same characters. Fig. 8. These eggs were laid by a Barred Rock pullet No. 5225. 22. V. CONCLUSIONS From the data obtained by scoring eggs laid by purebred and cross bred pullets it is possible to draw the following conclusions: 1. The egg quality criteria texture, contour, porosity and yolk movement are equally variable between the strains of Single Comb White Leghorns, Rhode Island Reds, Barred Plymouth Rocks, White Cornish x Barred Plymouth Rocks axd Dark Cornish x hhite Leghorns investigated in this study. 2. Egg shell texture in eggs of the Single Comb White Leg- horn did not vary between individuals of the breed. 5. Porosity is variable within the breeds observed. 4. Yolk movement is relatively the same for each individual within the Barred Plymouth Rock strain. 5. Contour did not vary significantly within the Rhode Island Red and Barred Plymouth Rock breeds observed. 23. VI. SUMMARY Eggs laid by the F1 generation of purebred Single Comb White Leghorns, Rhode Island Reds, Barred Plymouth Rocks, cross bred hhite Cornish x Barred Rocks, and Dark Cornish x hhite Leghorns were scored for external shell texture, contour, porosity, and yolk movement. Igg weight was recorded from a balance graduated to one-tenth of a gram. A method used by Perry (15), but revised and extended by Henderson (15) was used in scoring eggs for degrees of variance between breeds and within breeds. A method of analysis of variance as given by Baten (6) was emnloyed in comouting results. Variations between breeds, vith respect to a scoring range of from 1-5, for texture, contour, porosity, and yolk movement were not significant. The mean values were as given in appendix tables I to V. The mean veights of eggs in grams vere as follows: Rhode Island Reds 58.72; Barred Rocks 55.76; Single Comb hhite Leghorns 55.67; hhite Cornish x Barred Rocks 55.04; ard.Ihrk Cornish x hhite Leghorn 54.67. The differences between egg weights for the Rhode Island Red and Barred Rock, Single Comb “hite Leghorn, White Cornish x Barred Plymouth and Dark Cornish x White Leghorn were significant. The difference between the Barred Rock and the thite Cornish x Barred Rock was also significant. The other breeds are not significant be- tween themselves. Significant differences were found within.breeds for the follow- ing characters: 24. Texture Barred Plymouth Rock, Rhode Island Red, hhite Cornish x Barred Plymouth Rock, and Dark Cornish x hhite Leghorn. Contour Single Comb White Leghorn, Lark Cornish x thite Leghorn, and White Cornish x Barred Plymouth Rock. Porosity Single Comb White Leghorn, Rhode Island Red, barred Plymouth Rock, White Cornish x Barred Plymouth Rock and Dark Cornish x hhita Leghorn. Yolk Movement Rhode Island Red, White Cornish x Barred Plymouth Rock, White Leghorn, and Dark Cornish x White Leghorn. The following characters varied insignificantly within certain breeds: Texture Single Comb Vhite Leghorn Contour Rhode Island Red and Barred Plymouth Rock Yolk Movement Barred Plymouth Rock (l) (2) (4) (5) (6) (7) (8) (9) (10) (ll) (12) (14) 25. VII. LITERATURE CITED Almquist, H. J., 1955. The relationship of the candling appearance of eggs to their quality. Cal. Agri. Exp. Sta. Bull. 561. Almquist, H. J., and B. R. Burmester, 1954. Characteristics of an abnormal type of egg shell. Poul. Sci. 15: 116-122. Almcuist, H. J., and W. F. Holst, 1951. Variability of egg shell porosity in hen eggs. gilrardia 6: 61371. Asmundson, V. 8., 1951. II Determination of the shape of an egg. Scientific égriculture 11: 662-680. Atwood, d. J., 1917. Certain characteristics of hen eggs. West Virginia bxp. Sta. Bull. 166 . Baten, V. D., 1958. Elementary mathematical statistics New York. John Wiley and Sons, Inc. 1958. 558 pp. Curtis, M. R., 1914. Factors influencing the size, shape and physical constitution of the egg in domestic fowl. Maine Agri. Exp. Sta. Bull. 228 Fronda, F. M., and A. M. DeLaCruz, 1959. Studies on the physical qualities of the hen's egg. VII Variability of physical qualities of new—laid eggs prouuced in different laying periods. Philippine Agri. 28 525-551. Fronda, F. m., and D. D. Clemente, 1954. Studies on the physical qualities of the hen's egg. Philippine Agri. 25: 187-196. Funk, E.M., and n. L. Kempster, 1954. Egg weight in the domestic fowl. Mo. Agri. Exp. Sta. Bull. Hall, G. 0., 1958. Breed variations in egg characters Hays, F. A., 1957. Inheritance of egg size and egg characters. Mass. Agri. Exn. Sta. Bull. 544 Henderson, E. W., 1940. Criteria of egg quality. Unpublished data. Mich. Agr. Exp, Sta. Pearl, R., and F. M. Surface, 1910. A biometical study of egg production.in domestic fowl. III Variations and correlations in physical characters of the egg. U. S. Dep_. of Agri. Bureau of Animal IndustrygBull. 110. 26. (15) Perry, F. D., 1956. Influence of rations and storage on the ohysical characteristics of eggs. Iowa Agri. hxo. Sta. Bull; 192. (16) Taylor, L. 5., and J. H. Martin, 1928. Factors influencing thickness of egg shell. Poul. Sci. 8:59-44 (17) Van Ragenen, A. V., G. 0. Hall, and H. S. Wilgus, 1957. Variations in egg quality characters in certain breeds, varieties and strains of chickens. Journal of Agri. Res. 54: 767-777. 27. In the following tables are given the data as taken and condensed for use in this investigation. These data are in? cluded here for comparisons and references to the foregoing computations; and for the benefit of other students interested in individual breed variations in egg characteristics among poultry. I. AVERAGE Table l. INDIVIDUAL CHARACTER SCORES FOR EGGS - RHODE ISLAND RED. Bird No. Texture Contour Porosity Yolk Movement___ 5291 5.40 2.20 4.60 5.20 5295 2.55 1.55 5.66 1.17 5298 1.72 2.04 5.92 2.56 5299 2.24 1.71 5.52 2.58 5500 5.25 1.38 5.58 2.25 5501 5.00 1.66 5.00 1.66 5505 2.68 2.25 4.52 1.95 5505 2.18 2.55 4.12 1.94 5506 1.87 1.60 4.55 1.60 5509 1.90 2.24 5.81 2.14 5510 2.59 1.97 2.82 2.58 5511 1.25 1.25 4.25 2.25 Average 2.57 1.89 5.85 2.10 II-. Table 2. AVERAGE INDIVIDUAL CHARACTER SCORES FOR EGGS BARRED PLYMOUTH ROCK Bird No. Texture Contour Porosity Yolk Movement 5201 2.25 2.41 4.55 1.82 5206 4.70 2.21 4.68 2.00 5214 1.71 1.45 5.29 2.45 5215 2.64 2.14 5.59 2.18 5219 2.88 2.05 5.70 2.48 5221 2.22 5.17 5.55 2.17 5222 1.79 2.11 4.45 1.92 5225 4.79 5.54 4.69 5.08 5228 1.86 1.71 4.55 1.86 Average 2.76 2.51 4.04 2.21 III. Table 5. AVERAGE INDIVIDUAL CHARACTER SCORES FOR EGGS - WHITE LEGHORN BREED Bird No. Texture Contour Porosity Yolk Movement 5512 1.55 1.00 5.55 1.66 5515 1.46 1.58 1.84 1.69 5514 2.00, 2.00 4.55 2.50 5516 2.40 2.80 5.00 2.40 5522 2.07 1.86 5.86 2.71 5526 2.07 2.66 4.55 2.47 5552 2.25 1.75 4.86 5.00 5558 2.14 2.45 4.29 2.29 Breed average 1.97 1.99 5.98 2.54 Table 4. AVERAGE INDIVIDUAL CHARACTER SCORES FOR EGGS - DARK CORNISH AhD WRITE LEGHORN CROSS L— L Bird No. Texture Contour Porosity Yolk Movement 5260 2.00 2.28 5.80 2.52 5262 2.48 2.10 4.52 2.61 5265 5.69 2.62 4.85 2.51 5264 1.67 1.85 4.67 1.67 5265 2.65 2.05 5.00 2.65 5267 1.50 1.50 4.45 1.90 5272 1.60 1.80 4.40 2.40 5275 2.00 1.80 4.40 2.50 5278 2.50 1.90 5.45 1.80 5285 1.85 2.55 A 4.55 2.17 5288 1.76 1.86 5.59 2.41 Breed average 2.15 2.00 4.5141 2.50 V ll . \ i].l Oil. ix ‘1. v .. ll I‘IV‘ “‘ ilt‘ ' \l‘ 1“ i y All! 1]!" V. Table 5. AVERAGE INDIVIDUAL AND BREED CHARACTER SCORES FOR EGGS - WHITE CORNISH AED BARRED PLYMOUTH ROCK CROSS Bird No. Texture Contour Porosity Yolk Movement 5250 1.58 1.44 4.65 1.69 5251 2.15 2.18 4.94 2.50 5255 2.00 1.55 5.55 1.00 5256 1.76 2.14 4.05 1.48 5258 2.00 2.55 4.66 2.80 5246 .56 2.57 5.18 2.27 5249 2.25 2.08 4.05 2.15 5250 2.65 1.67 2.65 1.70 5251 5.51 2.05 5.88 2.41 5255 2.19 2.51 5.58 1.96 5257 5.00 2.00 5.25 1.75 5559 2.81 1.65 4.25 1.51 Breed average 2.54 1.98 5.92 .‘IQ .l I I1 I I I Table 6. A COMPARISON OF FREQUENCY OF EGG WEIGHTS AND THE TOTAL FREQUENCY FOR THE FIVE BREEDS OF POULTRY Breed Distribution Weight Barred White Barred Rocks Dark Cornish Rhode grams Rock Leghorn White Cornish White Leghorn Island Red 40-40.9 41~41.9 1 1 1 42-42.9 2 1 5 45-45.9 4 2 44-44.9 1 1 5 2 45-45.9 1 6 4 46-46.9 2 8 4 47-47.9 5 1 11 5 4 48-48.9 2 10 6 2 49-49.9 7 2 15 9 5 50—50.9 15 5 11 10 12 51-51'9 21 6 19 14 10 52-52.9 22 6 26 19 8 55-55.9 18 7 28 7 10 54—54.9 26 7 20 6 12 55-55.9 55 12 17 20 12 56-56.9 12 4 19 7 l2 57-57.9 50 6 10 9 12 58—58.9 8 5 12 11 9 59-59.9 15 4 6 17 17 60-60.9 7 4 6 11 61—61.9 6 1 2 5 15 62—62.9 6 1 6 5 65—65.9 5 1 4 10 64-64.9 2 5 20 65-65.9 2 1 4 14 66—66.9 2 8 67-67.9 5 67—67.9 5 68768.9 1 1 5 69-69.9 1 2 70-70.9 4 71—7l.9 2 72-72.9 5 ,9. H Total 242 74 255 ' 170 2 fry-FER a ‘- 59.94.1153 1333: ”THY .- $1.195... m 21 ’52 . M l“ . ' 'l‘- a N Y. T- 7 _ . . xii-17%;)???- 7. 77. - ‘y . 77." “t" '- ‘ I" i .1.‘ H 7| Li“ den}. . ‘ ' I ‘ . ‘ H w ‘5' . \‘ ~. ‘ ‘ r l ' ‘ V l y ‘Y n x 7 \ I 1 \ ‘ l 7» ‘ n I r x 7 7 ‘ ‘ ‘ . ' ‘ . ‘~ v y- 1' '. ‘ 7‘ , 7 » . A I ‘ . I . 7 7 V .. ‘ ‘ ' I z ‘ 7‘ ' ‘7‘ v ' , r ' 7 7 7 ‘77 7; ,. ' . 7. > ‘ . '0 l D > . 7 7 ,. v I | 7 ' \ ' ‘ A» . , ‘ I’M Aug7'“ ~ V » ‘ 7 7 ] V W49. V! N ' ‘ 7 . . 7: 7 7 W 7 .J ' ‘ wr,‘ 1‘ “ ‘ .7 ‘ - ‘ ‘ Eons '49 I "9 r ' r, I ») l LI ‘ 7 , ' ‘. Au" ‘ I ‘ M I: K ‘ a 7 ‘ ‘ . \ 1 ‘ 4 ' 7 7 7 4 ‘ ‘ } 7 . ‘ 7 7 4 ii .’ ‘ ~ \ v \ '7 v I ‘ i , 7 ' ‘ .7 7 w‘ 7 l ‘ y 7 L l . L l V f ‘ . l ‘V , ' ‘ 7 .\" ' y l i- ll -. . II I . r‘ I '1 I v i P ‘ 7 J . I ‘ f f 7? ~ c“.- —;al;':. .1‘?........._.__—““-‘ ‘ _ 1 :-.~.‘ -' -\-‘ “ , A . a «‘21; .2: l - .. 4 ~ 7 rs 1656.5 R666 154253 RobinSOn - .J-. \T656.5 R666 154258 v- \ Robinson "‘5 ‘ _ g ‘ . ‘77 Variations in certain physical 5f ' characteristics of eggs from 2 ‘ purebred & cross bred pullets. fl ; “ _ ”Rug7w4fi 1 7 i A L_,;_ ______ , , g i ,, _.. ‘ ‘ r» z y .7 m ,J Lilia- , c Tin: ‘7 , W- . 7 r "U 7' . :‘l E", ‘11 ' - ‘ ~57 ~ wy‘ " 7. 5! ' MT, “3‘ I; a »' :»4.; ‘ f ‘7 . 3.55? , L ' 7M‘u-l7”777177147717mu" 31293 03168 8082