Mice and rats represent the vast majority of research animals globally. Advancing rodent welfare beyond minimum standards — through housing, handling, and experimental design improvements — is a major welfare opportunity.
Rodent welfare refinement is one of the highest-leverage areas in laboratory animal welfare. The scale of use means even modest per-animal improvements translate into welfare gains for hundreds of millions of animals annually. Evidence-based refinements — social housing for social species, tunnel handling rather than tail-picking, nesting material, running wheels, and enriched environments — reduce chronic stress, improve animal health, and actually improve research quality by reducing stress-induced physiological variability. These are win-win improvements that should be standard practice across all institutions. Welfare refinement training for all personnel working with laboratory animals is an essential institutional investment.