Lighting programmes in broiler production significantly affect bird welfare through effects on activity, sleep, and stress. Evidence-based lighting standards are an achievable improvement for the industry.
Lighting welfare in broiler production has improved significantly from the days of near-continuous light, but ongoing management of light intensity, spectrum, and photoperiod continues to involve welfare trade-offs. Insufficient darkness prevents normal circadian rhythm development and sleep, causing chronic welfare compromise. Very low light intensity (dim lighting) reduces activity and injury risk but also reduces positive behaviour like foraging and exploration. Higher light intensity with adequate darkness periods supports more natural behaviour patterns but may require additional management. The welfare goal is lighting that enables natural behaviour, supports adequate sleep, and avoids the extremes of continuous light or inadequate illumination.