Rats and mice account for over 80% of all research animals used globally — an enormous population whose welfare is shaped by housing conditions, experimental procedures, and institutional culture in ways that have major implications for both animal welfare and research quality.
The welfare of research rodents is paradoxically both the most regulated and the most overlooked area of animal welfare — regulated through licensing and ethics review, yet overlooked because the scale is so large and the animals so small that welfare failures are easy to miss. Barren cages, social isolation, and inadequate pain management remain common in research facilities despite clear evidence that these conditions compromise both welfare and research quality. The alignment between welfare improvement and research improvement in rodent models is one of the strongest arguments for investing in refinement — better welfare produces better science.