Lighting management in broiler sheds profoundly affects bird welfare through its influence on activity levels, leg health, and natural behaviour expression.
Broilers kept under near-continuous bright lighting show higher rates of leg disorders, sudden death syndrome, and chronic fatigue compared to those given adequate rest periods. Very young chicks require continuous or near-continuous light for thermoregulation, but beyond the first week, regular dark periods improve welfare. Birds given periods of darkness are more active during light periods, show better leg health, and have lower mortality. Lighting enrichment using natural spectrum or blue-enriched light reduces fearfulness. Modern welfare standards increasingly specify minimum dark periods and light intensity ranges.