Table egg producers are switching to cage-free production systems as state legislation is passed requiring removal of conventional systems. Utilization of AVMA preferred depopulation methods may not always be feasible in cage-free systems due to complicated structure of building, size, resource availability, and concerns for worker safety. Additionally, carcass removal after mass depopulation in cage-free systems may be challenging due to onset of rigor mortis as hens have been observed grasping onto metal structure with feet because of perching reflex. Two experiments were conducted to improve current depopulation response in cage-free systems. Approximately 1,800 Lohmann Brown hens aged 56 weeks were housed in cage-free aviaries (Big Dutchman Natura 60) in 4 rooms (same hens and system were used in both experiments). In experiment 1, a combination of UV flash (1 pulse) and darkening of floor lights was examined on laying hens to elicit a movement response, particularly moving out of aviary system and onto floor area. Four treatments were as followed: 1) control, 2) UV lights flashed for 10-sec (UV), 3) floor lights turned off and UV lights flashed for 10-sec (DF+UV), and 4) floor lights turned off (DF). Results indicated that when UV flash was combined with darkened floors (DF+UV) in AM application, a greater difference in number of hens (P⁹́Þ0.05) was observed when compared to other lighting treatments; while in PM application, this difference was only apparent when comparing DF+UV to the control. UV light flash influenced hens' behavior, with more stress related behaviors (standing alert) apparent in both UV treatments, while more hens exhibited normal behaviors (preening and wing flapping) in non-UV light treatments. Although results demonstrated that usage of UV light moved hens to desired location (floor area), UV light flash may not be effective for long term movement since hens moved back into aviary within 6-min. In experiment 2, steam was assessed as an alternative "plus" for VSD+ depopulation. Four VSD+ treatments were as follows: 1) VSD+ heat to 40℗ʻC (VSD-H), 2) VSD with steam to 40℗ʻC (VSD-S), 3) VSD with heat to 40℗ʻC and then steam to maintain temperature (VSD-HS), and 4) VSD with steam to 40℗ʻC and then heat to maintain temperature (VSD-SH). Treatments that utilized steam caused laying hens to die in shorter times than VSD-H (P<0.0001). Results demonstrated steam can be an effective "plus" for VSD+ depopulation of laying hens in a cage-free system. While experiments emulated a commercial poultry environment, applications of techniques in present study still need to be evaluated in a commercial egg-laying facility.
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