Mice and rats are the most commonly used laboratory animals globally, and improving their welfare through better housing, enrichment, and social grouping is both ethically important and scientifically beneficial.
Laboratory rodent welfare is a welfare-science alignment case: the same housing improvements that reduce animal suffering also improve the quality and reproducibility of research data. Stressed, isolated mice produce different physiological responses than socially housed, enriched animals -- meaning that poor welfare produces poor science. Despite this, single housing and barren cage environments remain common in many facilities, often justified by contamination prevention concerns that careful management can address. The regulatory and institutional framework for rodent welfare has improved substantially in the past 20 years, but implementation lags standards in many facilities globally.