Research on pig enrichment has identified the specific properties of materials that genuinely meet pig behavioral needs versus token provision that does not reduce frustration or improve welfare.
Pig enrichment research has moved beyond the question of whether enrichment helps (it does) to the more practically useful question of what specifically works and why. The answer is clear: enrichments that can be rooted, chewed, destroyed, and that change over time meet pig behavioral needs in ways that rigid, indestructible hanging objects cannot. A pig that can root through straw, chew and shred it, and redistribute it in the pen is engaging in species-appropriate behavior that reduces frustration, stereotypies, and tail biting. A pig that can mouth a chain for 10 seconds before losing interest is not. Regulatory compliance that allows chain provision as adequate enrichment represents a failure of regulatory intent — and EFSA has now formally stated this. The transition to effective substrate enrichment requires infrastructure investment that regulators and certification schemes should require.