Lighting management in poultry houses profoundly affects chicken welfare, activity levels, and health. Evidence-based lighting programs can significantly improve broiler and laying hen welfare with minimal cost.
Lighting is one of the most tractable and cost-effective welfare interventions available in poultry production, yet it remains poorly standardized across the industry. The welfare harm of continuous or near-continuous lighting — historically used to maximize feeding time — is substantial: sleep deprivation causes immune suppression, chronic stress, and ocular damage in broilers whose rapid growth already compromises their physiology. Providing minimum 6-hour dark periods, now required in EU broiler production, dramatically improves sleep opportunity and reduces associated welfare costs. Light intensity is equally important: very bright lighting causes fearfulness and chronic stress; very dim lighting suppresses natural activity while appearing to reduce injurious pecking. An intermediate intensity that allows behavioral expression while managing aggression represents the welfare optimum. Gradual dimming programs — simulating dusk and dawn — reduce the panic stampedes that sudden light changes cause in large poultry flocks, preventing injuries that are common during abrupt lighting transitions. LED systems with these capabilities are commercially available and cost-effective at commercial scale.