The lighting regimes used in poultry houses significantly affect chicken welfare through their effects on circadian rhythms, sleep, activity levels, and health outcomes.
Lighting welfare in poultry represents a clear case where industry standard practice causes significant harm for productivity reasons. Continuous light suppresses normal sleep architecture, causing chronic physiological stress. Sleep-deprived chickens show impaired immune function and reduced recovery from illness. Minimum dark periods are a low-cost welfare improvement with measurable positive outcomes. The Better Chicken Commitment requirements for meaningful dark periods represent good science translated into production standards. Consumer pressure through scheme-certified purchasing directly drives adoption of better lighting practices.