Lighting programs in broiler chicken production significantly affect behaviour, health, and welfare, with evidence-based standards increasingly requiring minimum dark periods and appropriate light intensity.
Lighting management in broiler houses has profound effects on welfare that were systematically ignored for decades. Continuous or near-continuous lighting, used to maximise eating and growth, severely disrupts natural circadian rhythms and suppresses normal behaviours. Dark periods are essential for rest, sleep, and physiological restoration. Appropriate light intensity and spectrum affect activity levels, bone development, and fearfulness. The science supporting minimum dark period requirements and species-appropriate lighting is robust, and regulatory minimum standards in the EU reflect this. However, global broiler production outside regulated markets frequently operates without these standards. Consumer and retailer pressure for supply chain welfare standards is an important driver of improvement beyond regulatory minimums.