Standard laboratory animal housing in bare cages fails to meet the behavioral needs of most species, and the provision of environmental complexity is both a welfare requirement and scientifically beneficial.
Laboratory animal housing welfare is paradoxically relevant to scientific quality as well as ethics: animals in chronic stress from barren environments produce stress-altered physiological data that may confound experimental results. The provision of nesting material, shelter, and social housing for group-living species is simultaneously a welfare improvement and a scientific quality improvement. Regulatory requirements for environmental enrichment in laboratory animals are increasing globally, but implementation is inconsistent. Researchers and institutions that invest in enrichment programs serve both the welfare of the animals in their care and the validity of the science they produce.