Broiler Lighting Regimes and Welfare

The lighting regimes used in broiler chicken houses significantly affect welfare through their influence on rest, activity, growth rate, and access to the natural day-night cycle that poultry require for biological regulation.

Key Facts

Historically, broiler houses used near-continuous lighting (23 hours light, 1 hour dark) to maximise feed intake and growth rate
Near-continuous light causes sleep deprivation, altered circadian rhythms, and is associated with increased leg health problems
EU law now requires a minimum dark period of 8 hours per 24-hour cycle in broiler production
Dim light periods rather than full darkness can prevent normal rest if light intensity is insufficient for melatonin secretion
Broilers given access to natural daylight or full spectrum artificial light show better bone mineralisation and activity budgets
LED lighting systems allow programmable spectra, intensities, and photoperiods that can be tuned for welfare rather than just production
Research shows that appropriate dark periods reduce mortality, improve leg health, and have minimal negative impact on growth efficiency
Coloured light (blue wavelengths) can reduce aggression in stressed flocks, with welfare implications for managing high-density housing

Welfare Considerations

Lighting is a fundamental environmental variable for broiler welfare because it regulates circadian biology, sleep, activity patterns, and hormonal rhythms. Near-continuous lighting was adopted to maximise growth but at significant welfare cost: chronically sleep-deprived birds with disrupted circadian function suffer measurably worse welfare outcomes across multiple indicators. The switch to minimum 8-hour dark periods required by EU legislation represented a meaningful welfare improvement, but implementation varies and some dark periods use insufficiently dark or quiet conditions to enable genuine rest. Optimal welfare lighting for broilers involves appropriate dark periods, dimming transitions that allow the birds to settle before lights-out, and light spectra that support natural activity and bone development. These improvements are largely achievable without meaningful production loss and represent a high-value welfare intervention.

What You Can Do

Support certification schemes that require minimum dark periods and appropriate lighting spectra for broiler welfare
Advocate for mandatory lighting welfare standards in national poultry regulations beyond the EU minimum
Choose chicken products from producers that publish their lighting regime as part of welfare transparency reporting
Support research into optimal lighting parameters for broiler welfare across different housing systems
Encourage poultry equipment manufacturers to design lighting systems with welfare as a primary specification