Mice are highly social animals whose welfare in laboratory settings is significantly influenced by housing conditions, with group housing providing essential social needs.
Single housing of mice represents a significant welfare compromise that should be justified scientifically and minimised in duration. The social needs of mice are genuine and isolation creates measurable stress. However, group housing of males requires careful management to prevent wounding. Best practice involves providing appropriate enrichment, stable group composition from weaning, and monitoring for aggression. The welfare benefit of social contact generally outweighs the risks when housing is well managed.