Lighting conditions profoundly affect laying hen welfare. Photoperiod, intensity, spectrum and access to natural light influence behaviour, health and productivity.
Lighting management is a welfare tool with significant positive and negative potential in poultry systems. Manipulating light to suppress activity — a common practice in some systems — reduces observable welfare problems during audits while masking chronic stress that manifests when conditions are assessed properly. Welfare-positive lighting provides adequate darkness for rest, appropriate intensity for normal social behaviour, UV wavelengths for perceptual accuracy and, ideally, natural daylight access. Systems that use lighting primarily to maximise production metrics rather than support welfare compromise hen quality of life in ways that aggregate audit scores may not capture. Evidence-based lighting standards are available and should be incorporated into welfare certification.