Dust bathing is one of the most strongly motivated natural behaviours in laying hens, and its frustration in barren or inadequate housing systems causes significant welfare harm through displacement behaviour and chronic motivation deprivation.
Dust bathing motivation is one of the most robustly demonstrated welfare needs in laying hens. The fact that hens perform vacuum dust bathing on bare wire floors — despite receiving no functional benefit from the behaviour — demonstrates that the drive to perform the behavioural sequence is intrinsic and persistent. When motivation is finally satisfied by substrate access after deprivation, hens show rebound bathing that is prolonged and intense — the physiological signature of a need that has been denied. Welfare systems that include appropriate dustbathing substrate are not providing a luxury; they are meeting a documented biological need. The quality of litter in cage-free systems matters as much as its presence: compacted or wet litter prevents the loose particle contact that makes dust bathing behaviourally and functionally effective. Maintaining dry, loose substrate is a continuous welfare management challenge in cage-free housing.