Enrichment for laboratory animals — providing complexity, social contact, and behavioural opportunities — improves welfare and often improves research quality. The 3Rs framework (Replace, Reduce, Refine) mandates refinement through enrichment.
Laboratory animal welfare exists at the intersection of ethical obligation and research quality. Stressed, impoverished laboratory animals are not only suffering — their abnormal physiology introduces variation that reduces the reliability and reproducibility of research results. Enrichment is therefore simultaneously a welfare intervention and a scientific quality improvement. The most important enrichment elements for laboratory rodents — nesting material, social housing, hiding spaces, gnawing items — are inexpensive and widely supported by evidence. Welfare assessment of novel animal models (particularly transgenic models with disease phenotypes) requires proactive monitoring throughout the animal's life, not just at procedure endpoints.