Pen design significantly affects the ability of pigs to express natural behaviors and avoid aggression, with major welfare implications.
Pen design welfare impact is often underestimated because it creates the environmental constraints within which all other welfare decisions play out. A well-designed pen enables welfare through its layout; a poorly designed pen creates welfare problems regardless of other management investments. Round corners, spatial separation of functions, retreat spaces, and integrated enrichment represent design investments that pay welfare dividends across all the animals that use them. The economic case for welfare-positive pen design is supported by reduced injury treatment costs, lower tail biting rates, and improved growth efficiency. Retrofitting existing facilities is possible but capital investment in new facilities provides the opportunity to incorporate welfare design principles from the start.