Journal of Applied Poultry Research (Sep 2023)
Can UV light induce movement in cage-free laying hens?
Abstract
SUMMARY: In recent years, more farms have been transitioning to cage-free systems as multiple states passed regulations banning use of conventional cages, and several large food service companies pledged to exclusively source cage-free eggs by 2025–2026. However, transition and management of hens within new cage-free systems has been problematic. Additionally, catching hens prior to mass depopulation or carcass removal after depopulation becomes a challenging task for workers in these systems. The goal of this study was to explore 10-sec flashes (2 pulse/d, 1 pulse in AM and 1 pulse in PM) of UV light and darkness as management tools to stimulate a movement response from laying hens, with the aim of moving hens from within the aviary system to floor area. Approximately 1,800 Lohmann Brown hens were divided into 4 rooms equipped with Big Dutchman Natura 60 aviary; 150 hens were placed into 3 sections of aviary, totaling 450 hens per room. Six UV-light bars in the 395 to 400 nm wavelength were used. Four lighting treatments were as followed: 1) Control, 2) UV light flashed for 10-sec (UV), 3) floor area was darkened (DF), and 4) UV flashed for 10-sec plus floor area darkened (DF + UV). Each treatment was applied once in the AM and once in the PM. Videos were recorded to assess hens’ spatial distribution (difference in number of hen pre- and post-treatment application) and behavior (preening, dust bathing, wing flapping, perching, and standing alert), before and after treatments were applied. Results demonstrated that when UV flash was combined with darkened floors in AM application, a greater difference in number of hens was observed in this treatment compared to other lighting treatments; whereas in PM application this difference was only observed when comparing DF + UV to control. UV light flashes influenced hens’ behavior, with more stress related behaviors apparent in treatments where UV lights were used, whereas more hens exhibited normal behaviors in non-UV light treatments. Based on these observations, a flash of UV light was successful in moving laying hens out of aviary and onto floor area, but this was only effective for a short period and may not be effective for long-term movement.
