Lighting conditions profoundly affect poultry welfare. Research on light duration, intensity, spectrum, and flicker rate has produced evidence-based recommendations that improve welfare in commercial production.
Poultry lighting is a welfare lever that is well-studied yet inconsistently applied in commercial production. The evidence for a minimum dark period of 8 hours is strong from welfare science, yet economic incentives favor maximal light and continuous growth that conflicts with birds getting adequate sleep. The invisible suffering of sleep-deprived broilers is not apparent to consumers who see only the final product; it manifests in elevated stress hormones, impaired immune function, and behavioral changes that are measurable by researchers but invisible at market. Implementing evidence-based lighting standards requires either regulatory mandate or certification requirements that create market incentives for welfare-aligned lighting management.