Evidence that pigs experience positive emotions including play, curiosity, and social engagement has transformed understanding of their welfare needs. Designing environments that enable positive experiences is the frontier of pig welfare science.
The recognition that pigs experience positive emotions transforms welfare assessment from measuring absence of suffering to measuring presence of positive experiences. An environment that prevents obvious suffering but provides no opportunity for play, curiosity, or social engagement fails a complete welfare standard. The practical implication is that designing pig environments to enable positive experiences - varied enrichment, social play opportunities, positive human contact - is a legitimate and important welfare goal beyond simple harm prevention.