Laboratory mice are the most commonly used research animals globally, and improving their housing through enrichment and appropriate social housing significantly improves welfare without compromising research.
The traditional 'clean' laboratory mouse cage - an empty plastic box with bedding - denies mice their fundamental behavioral needs for exploration, nesting, social interaction, and play. This welfare deprivation is not only an ethical concern but may compromise research validity by creating chronically stressed animals with abnormal physiology. The 3Rs framework (Replace, Reduce, Refine) applied to laboratory mouse housing supports provision of nesting material, shelters, and social housing as default standards rather than optional additions.