Light exposure in broiler chicken houses profoundly affects growth, behavior, health, and welfare. Understanding lighting science helps consumers and producers advocate for better standards.
Broiler lighting management is one of the most powerful and lowest-cost welfare interventions available to producers. Conventional dim continuous lighting suppresses natural activity cycles, produces sedentary birds with poor muscle and bone development, and contributes to the lameness endemic in modern broiler production. Birds kept in near-darkness also show impaired immune development and higher susceptibility to respiratory disease. Higher light intensity (minimum 50-100 lux) and proper dark periods (minimum 8 hours) produce more active birds with better leg health and lower mortality. Providing UV-B light allows broilers to synthesize vitamin D naturally, improving calcium metabolism and bone strength. Natural light windows benefit welfare and are increasingly required by higher-welfare certification schemes. The economic cost of welfare lighting improvements is modest compared to the benefit in reduced lameness and mortality.