Space allowance per pig is one of the most significant determinants of welfare in intensive production, affecting aggression, stereotypic behaviour, skin lesions and performance indicators.
Space allowance affects pig welfare through multiple pathways simultaneously. Crowded pigs cannot avoid aggression, are forced to lie in fouled areas, cannot express foraging behaviours and are more likely to develop respiratory infections through increased pathogen exposure. Even modest increases above minimum space allowances produce measurable welfare improvements.