Modern pig pen design integrates positive welfare principles including enrichment, rooting substrates, and space allowances that support natural behavior expression.
Pen design has profound effects on pig welfare; barren concrete environments cause chronic boredom, frustration, and redirected aggression including tail biting and cannibalism. Providing straw, hanging toys, and rooting substrates costs relatively little but prevents significant suffering. Welfare-positive pen design is not just ethical - it improves animal health and reduces losses.