Lab Mouse Enrichment Standards | Animal Welfare Hub

How environmental enrichment for laboratory mice improves welfare and reduces variability in research results.

Key Facts

Mice are the most commonly used laboratory animal globally with hundreds of millions used annually
Standard lab mouse housing is often barren, with wire grid floors and minimal environmental complexity
Nesting material is one of the most important enrichments for laboratory mice and is strongly motivated
Shelter provision reduces stress indicators and thermal regulation problems in laboratory mice
Enriched housing reduces behavioral variability, potentially improving research reproducibility

Welfare Considerations

Laboratory mouse enrichment has both welfare and scientific justifications. Mice in barren cages show elevated stress hormones, abnormal repetitive behaviors, and compromised immune function. Enrichment including nesting material, shelter, and running wheels reduces these welfare problems while also producing less stressed, more physiologically consistent animals that may give more reproducible research results. Despite this dual justification, enrichment implementation remains variable across institutions, often due to concerns about contamination risk or cage change complexity that evidence suggests are manageable.

What You Can Do

Advocate for mandatory enrichment standards including nesting material for all laboratory mice
Support institutional animal care committees that enforce enrichment requirements
Donate to laboratory animal welfare organizations advancing enrichment science
Engage with the 3Rs framework to promote enrichment as a standard refinement measure