Space allowance is one of the most fundamental determinants of pig welfare in intensive systems. EU Directive 2008/120/EC sets minimum space requirements, but research consistently shows these minima are insufficient for adequate welfare expression.
Pigs at EU minimum space allowances cannot all lie down simultaneously in lateral lying positions — the natural rest posture — without contact. Crowded pigs show elevated cortisol, increased aggression, and higher injury rates. Social disruption from crowding reduces time spent in positive social activities including play and affiliative grooming. Space allowance interacts with enrichment and housing design: even small increases in space provision combined with enrichment substrate can dramatically improve welfare outcomes. Higher-welfare systems with additional space show measurably lower tail biting rates, lameness, and respiratory disease, creating a welfare-productivity co-benefit case for space allowance increases.