Behavioral and Production Responses of W-36 Chicks to Supplementary UVA Light

UVA (315-400 nm) light perception is an essential part of poultry vision, which may be used to modify behavioral traits of birds such as feeding, peer recognition, and social encounters. The objectives of this study were to assess behavioral and production responses of W-36 chicks reared under LED light with or without various levels of UVA supplementation (0%, 5%, 10%, and 15%), i.e., LED+UVA vs. LED. For behavioral response, a total of 108 chicks (day-old) in 18 groups were assessed for their lighting preference. Each group of chicks was involved an 8-d preference test, during which the birds could move freely between two inter-connected compartments that contained LED and LED+UVA, respectively. For production response, a total of 180 chicks (day-old) in 12 groups were used to assess the effects of the UVA supplementation (5%) on growth performance of chicks. For each batch, two groups were randomly assigned to two compartments, one with LED and the other with LED+UVA. In the scenario of 0% vs. 5% UVA, the chicks spent significantly lower amount of time under LED+UVA than under LED (45.6% vs. 54.4%), but had comparable feed use under both light conditions. In the scenario of 0% vs. 10% UVA, the chicks showed similar amount of time spent and feed use. In the scenario of 0% vs. 15% UVA, the chicks spent significantly higher proportion of time (61.3% vs. 38.7%) and consumed significantly more feed (60.5% vs. 39.5%) under LED+UVA than under LED. Chicks had comparable growing performance under LED and LED+UVA (5%) and no eye pathology was detected at 5% UVA supplementation level. The study demonstrates the attracting effect of UVA light at 15% inclusion rate under LED illumination on chicks in terms of time spent and feed use. A large-scale and long-term study to further verify the positive effects of UVA inclusion seems warranted.