Mice are the most widely used laboratory animal. Despite regulatory protections, most lab mice experience significant welfare deficits that impair both their wellbeing and research quality.
Laboratory mice exist at the intersection of science and welfare — their use produces medical knowledge that benefits humans, but often at significant cost to their own wellbeing. Standard laboratory housing conditions are dramatically below what mice need to thrive: no nesting material, no hiding areas, often no social companions, fluorescent lighting without dark refuges. These conditions cause chronic stress that alters the very biological systems researchers are trying to study — undermining both welfare and scientific validity. Enriched housing with nesting, shelters, and social companions improves welfare and is increasingly recognized as improving research quality by reducing stress-induced biological variation. The scientific and ethical case for better lab mouse welfare is now well established.