Scientific evidence on what enrichment materials best meet the behavioural needs of pigs helps distinguish genuinely effective enrichment from token provision that fails to satisfy motivated behaviours.
Not all enrichment is equal. The scientific evidence is clear that pigs are motivated to root in manipulable substrates — they will root vigorously in straw, compost, or soil in ways that suspended chains or hard plastic simply do not satisfy. Research comparing tail biting rates and welfare indicators between farms providing straw versus hard objects consistently finds straw superior. The challenge for higher-welfare advocacy is moving beyond legal compliance with enrichment requirements toward quality standards that actually fulfil pigs' behavioural needs.