Effects of lighting program at different periods on broiler chicken performance

Abstract

Researchers have not yet definitively established the optimal lighting program and dark period initiation for improving the welfare, health, and performance of commercial broilers. Therefore, this study aims to examine how different lighting schedules at various ages affect key factors, including growth performance and mortality rates, in broiler chickens. 400-day-old Ross chicks were assigned to four experimental groups using a completely randomized design. Each group consisted of five replicates with 20 chicks in each. The experimental groups were as follows: T1 was exposed to 24 hours of continuous light, while the other three groups experienced a daily dark period of five hours. Specifically, T2 began its dark period after the first week, T3 after the second week, and T4 after the third week. The broiler chickens in the T2 experimental group showed significantly better performance compared to the other groups (P<0.05). Furthermore, all experimental groups that experienced 5 hours of darkness demonstrated an improved feed conversion ratio (P < 0.05), with no significant changes observed in feed intake or mortality rates (P > 0.05) over the 42 days. In conclusion, providing 5 hours of darkness after the first week of age significantly improved the feed conversion ratio without decreasing feed intake. Chickens subjected to this lighting regimen also showed better weight gain compared to those kept under continuous lighting programs. Therefore, it is recommended to raise broiler chickens on a 19-hour light and 5-hour dark (19L:5D) schedule following the first week of age to promote optimal growth and health.