Laboratory rodents are the most numerous animals used in research, and advances in housing, enrichment, and pain management have significant welfare implications for this large population.
Laboratory rodent welfare affects more animals than any other aspect of research animal care given the scale of use. Advances in understanding mouse and rat behavioral needs have shown that traditional individual housing causes chronic stress that both compromises animal welfare and affects the scientific validity of stress-sensitive research. Social housing with enrichment improves welfare and produces more generalizable research results — a case where welfare and scientific quality are aligned. The 3Rs principle provides a framework for progressive welfare improvement throughout research practice.