Laboratory Mouse Enrichment: From Standard to Best Practice

Laboratory mice are the most commonly used research animal, yet their welfare in research settings varies enormously. Evidence-based enrichment is moving from optional to expected in responsible research institutions.

Key Facts

Mice are the most commonly used laboratory animal globally, with over 100 million used annually in research
Barren housing causes stereotypic behaviors in mice including bar-chewing, repetitive circling, and excessive grooming
Nesting material is among the most impactful and low-cost enrichment items for mice, significantly reducing stress indicators
Running wheels reduce stereotypy and stress in mice and do not confound most research outcomes
Social housing reduces stress in both male and female mice, though male mice can show aggression requiring management
The EU Directive 2010/63/EU specifies minimum housing requirements for laboratory mice including environmental complexity
Research councils including the NC3Rs provide guidance on evidence-based enrichment that improves welfare without compromising research validity

Welfare Considerations

Laboratory mouse welfare has been transformed by decades of enrichment research that has demonstrated unambiguously that enriched housing produces less stressed, healthier animals whose data quality is actually improved by better welfare. The argument that enrichment confounds research outcomes has been largely refuted - stressed, stereotypy-displaying mice in barren environments are the confounded model, not enriched ones. The remaining gap is implementation: institutions that understand enrichment best practices must translate this into standard housing across all mouse facilities. The welfare-science-research quality alignment is the strongest possible argument for enrichment adoption: providing better welfare produces better science. This framing makes enrichment investment compelling to research institutions with both welfare and scientific quality commitments.

What You Can Do

Support research institutions that publish their laboratory animal welfare standards including mouse enrichment provision
Advocate for NC3Rs enrichment guidelines to be adopted as minimum standards by funding bodies and research institutions
Support development and validation of non-mouse research models that can replace or reduce mouse use for specific research questions
Ask pharmaceutical companies and research institutions about their laboratory animal welfare standards when engaging with their work
Support public funding for the 3Rs research that continues to develop welfare refinements for laboratory mouse housing