Lab Mouse Social Housing: Evidence-Based Refinement

Laboratory mice are social animals that suffer when housed alone, yet single housing remains common in research settings - evidence-based reform is improving welfare for millions of research animals.

Key Facts

Approximately 60-70% of laboratory mice used in UK research are housed in groups
Single housing of mice causes chronic stress, elevated corticosterone, and increased aggressive behaviour when introduced to conspecifics
Male mice can be aggressive when housed together, but this is manageable with appropriate group composition and housing
Female mice benefit from group housing without the aggression management challenges seen in males
Providing hiding places, nesting material, and environmental complexity reduces male mouse aggression in group housing
The NC3Rs recommends group housing as the default, with single housing requiring justification in project licence applications
Transparent dividers allowing olfactory but not physical contact can provide social stimulation for temporarily single-housed mice

Welfare Considerations

Mouse social housing is one of the most tractable refinement interventions available in animal research. The welfare evidence is clear: singly housed mice are chronically stressed, affecting both their welfare and the reliability of research data. The practical challenges (male aggression, infection control) are real but manageable with appropriate housing design and management protocols. Research institutions committed to the 3Rs should treat group housing as the mandatory default and single housing as a justified exception requiring welfare rationale, not the reverse.

What You Can Do

Advocate for group housing as the mandatory default in laboratory mouse housing standards
Support NC3Rs and similar organisations publishing practical guidance on mouse social housing
Ask research institutions about their mouse housing policies and single housing justification requirements
Donate to research into mouse-appropriate housing designs that manage aggression in group settings
Engage with consultation processes on laboratory animal welfare standards to support social housing requirements