Pigs have complex cognitive and behavioural needs that require environmental enrichment to prevent boredom, stereotypies and aggression in intensive production systems.
The welfare benefits of pig enrichment go beyond preventing specific problem behaviours to supporting fundamentally better psychological states. Pigs that can express natural rooting behaviour, engage with novel objects and play with pen mates demonstrate positive affective states that barren intensive environments completely deny. The legislation requiring manipulable material represents a minimum rather than adequate standard - hanging chains or sticks provide far less enrichment than the deep rooting substrates pigs genuinely prefer. The research demonstrates clearly that enrichment reduces cortisol, reduces aggression, reduces tail biting and improves immune function - welfare improvements that translate directly into better health outcomes.