Lighting management in broiler houses has significant welfare implications that are often underappreciated. Light duration, intensity, wavelength, and the provision of adequate dark periods all affect broiler behavior, health, and welfare. Evidence-based lighting programs improve welfare while also supporting productivity.
Chickens evolved with natural light cycles governing circadian rhythms, sleep-wake patterns, and hormone regulation. Commercial broiler houses historically provided near-continuous light (23 hours on, 1 hour off) to maximize feed consumption and growth rate. This severely disrupts circadian rhythms, reduces sleep quality, and is associated with skeletal disorders, cardiovascular problems, and immune suppression.
Research demonstrates that providing minimum 6 hours of continuous darkness daily significantly improves broiler welfare: better circadian rhythm regulation, improved sleep quality, reduced lameness incidence, and lower mortality rates. EU broiler directive (2007/43/EC) requires minimum 6 hours dark, with at least 4 continuous. Higher welfare standards (Better Chicken Commitment) require 8 hours of darkness.
Minimum light intensity of 20 lux in broiler houses is required by EU law. Higher intensities (50+ lux) support natural behavior expression, foraging activity, and reduce fearfulness. Dim lighting suppresses activity and has been associated with higher lameness scores.
Chickens can see into the ultraviolet spectrum. LED lighting with appropriate spectral composition supports better visual environment than conventional fluorescent lighting. Red-shifted lighting can reduce aggression in some contexts; blue-enriched lighting supports circadian rhythms. Research is developing evidence-based wavelength recommendations.
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