Circadian rhythm disruption in pigs from artificial lighting systems affects welfare through its impacts on sleep, hormone production, and behaviour.
Circadian rhythm disruption represents a welfare cost from intensive housing systems that is often overlooked. Pigs deprived of natural light cues cannot regulate their physiological rhythms normally, potentially affecting immune function, reproduction, and behaviour. Programming artificial lighting to mimic natural day length variation with dawn and dusk transitions costs little but may provide meaningful welfare benefit through restored circadian rhythm regulation.