Lighting programs in broiler chicken production profoundly affect behavior, health, and welfare through manipulation of activity patterns and growth rates.
Lighting manipulation in broiler production represents a form of welfare compromise that is often invisible to consumers. Extended light periods exploit chickens' natural feeding responses to increase growth rates, but create chronic welfare costs including fatigue, eye problems, and leg disorders. The chickens are prevented from experiencing natural day-night rhythms that are fundamental to vertebrate health. Simple reforms - providing adequate darkness and better quality lighting - significantly improve welfare with minimal production cost impact.