Scientific research on pig enrichment has identified specific materials and activities that most effectively meet behavioral needs and reduce suffering in commercial production systems.
Pig enrichment science has moved from the general recognition that enrichment is beneficial to the specific identification of what works and why. Straw — the most effective enrichment material — works because it meets multiple behavioral motivations simultaneously: pigs can root through it, carry it for nesting, investigate it for food, and manipulate it orally. Regulatory-minimum enrichment of chains and rubber tubes fails because it meets almost none of these needs. The welfare gap between straw-bedded systems and chain-enriched slatted systems is enormous despite both technically meeting minimum EU requirements. Welfare-effective enrichment requires matching the enrichment to the specific behavioral motivations it needs to satisfy.