Dust bathing is one of the strongest behavioural motivations in hens, and its frustration in cage systems causes significant welfare harm through a recognised vacuum behaviour.
Dust bathing is not merely a preference but a hardwired motivational drive in chickens. Hens in battery cages perform incomplete, frustrated dust bathing movements on bare wire floors, indicating persistent motivation without satisfaction. This vacuum behaviour is a recognised welfare indicator. Even enriched cages with small dustbathing areas provide inadequate substrate. Free-range and organic systems allowing genuine dust bathing on appropriate substrate best meet this welfare need.