Providing environmental enrichment for laboratory mice significantly improves their welfare and can enhance the reliability of research results by reducing stress-related variables.
Standard laboratory mouse caging was historically designed for ease of cleaning and containment, not animal welfare. Mice in barren cages without nesting material, social contact, or environmental complexity show elevated baseline stress that affects physiology, behavior, and experimental outcomes. The welfare and scientific cases for enrichment are therefore complementary: reducing mouse stress produces calmer, healthier animals whose physiology more accurately reflects the conditions being studied. Providing nesting material — inexpensive and widely available — is now considered an ethical obligation and scientific best practice in most research ethics frameworks.