Research on pig enrichment has advanced significantly, identifying which materials and designs genuinely improve welfare versus those that provide only superficial compliance with regulations.
Enrichment science has moved far beyond simply providing something in the pen. Regulatory compliance — hanging a chain from the ceiling — does not satisfy the behavioral needs that enrichment is designed to meet. Pigs are highly motivated to root, chew, and investigate novel substrates; these behaviors are suppressed in barren environments but restored by appropriate materials. The evidence hierarchy is clear: organic, manipulable materials that can be destroyed and consumed are far more effective than rigid objects. Straw meets multiple behavioral needs simultaneously — rooting, ingestion, thermal comfort, and nest-building motivation. The welfare argument for straw is so strong that it is increasingly being used as the benchmark against which other enrichment materials are compared. Pen space for enrichment use also matters — crowded pigs cannot use enrichment effectively.