Dust bathing is a highly motivated behavioral drive in chickens that serves both physical and psychological functions. Depriving hens of suitable dust bathing substrate is a significant welfare deprivation.
Dust bathing is not a behavioral luxury for hens — it is a biologically essential behavior that they are strongly motivated to perform regardless of whether it is effective. The persistence of vacuum dust bathing in caged hens — going through all the motions on bare wire — demonstrates the strength of this behavioral drive even when the substrate is absent. This is a form of chronic frustration that is a direct welfare harm of battery cage systems. Cage-free systems that provide appropriate litter in adequate quantity restore the ability to perform this behavior properly, representing a fundamental improvement in behavioral freedom. Litter management, substrate choice, and provision of dust bathing areas are important welfare considerations in cage-free housing design.