How pen design decisions in commercial pig production affect pig welfare and what evidence-based design principles look like.
Pen design is a structural determinant of pig welfare that operates continuously throughout the animal's life, unlike management interventions that can be applied inconsistently. A pen that is too small, poorly shaped, or lacks appropriate flooring creates welfare problems regardless of how skilled the stockperson is. Evidence-based pen design — appropriate space allowances, substrate access, solid lying areas, water access distributed to reduce competition, and design features that reduce agonistic interactions — represents a foundational welfare investment with lasting impact. Designing welfare into buildings is more reliable and ultimately more cost-effective than attempting to compensate for design failures through management.