Rodents constitute over 95% of animals used in biomedical research. Welfare refinements in how they are housed and handled can significantly improve their quality of life without compromising scientific validity.
Laboratory rodents represent the largest category of research animals by number, and their welfare has historically received less attention than larger species despite the scale of impact. Standard laboratory housing often fails to meet rodent behavioral needs for nesting material, burrowing, hiding, and social interaction. Simple refinements have strong evidence supporting welfare improvement: tunnel handling instead of tail picking, nesting material in all cages, environmental enrichment, and optimized social housing. These refinements also frequently improve scientific validity by reducing stress-induced variability in experimental outcomes. The welfare and scientific cases for refinement align unusually well.