Artificial lighting regimes in commercial poultry production are manipulated for production efficiency, with welfare implications from disrupted circadian rhythms and chronic light manipulation.
Light manipulation in commercial poultry production prioritizes productivity over welfare in ways that have significant but underappreciated consequences. Broilers kept under near-continuous dim lighting cannot rest properly during natural sleep periods, disrupting biological rhythms that govern immune function, metabolism, and behavior. Laying hens subjected to lighting manipulations for forced molting experience acute physiological stress. The complete absence of natural light in windowless buildings deprives birds of the environmental variation and behavioral stimulation provided by natural photoperiod. Sudden light changes cause flock-wide panic responses with associated trampling injuries. These are preventable welfare costs whose benefits primarily accrue to producers rather than birds.