Dust bathing is an essential natural behavior for chickens and other poultry. Denying it causes frustration and compromised welfare. Providing appropriate substrate is a basic welfare requirement.
Dust bathing is one of the clearest examples in animal welfare science of a behavioral need that cannot be suppressed by environment — only frustrated or fulfilled. Hens on wire or solid floors without substrate perform vacuum dust bathing, going through the complete behavioral sequence on bare surfaces. This is a direct welfare indicator: the motivation is so strong it drives behavior even when it cannot achieve its function. Providing litter fulfills this motivation and is associated with improved feather condition and reduced stereotypic behavior. The requirement is technically simple and inexpensive — loose substrate in sufficient depth — making its absence in conventional systems a straightforwardly avoidable welfare failure.