Research consistently shows that excessive stocking density in pig housing increases aggression, disease transmission, stress hormones, and reduces overall welfare outcomes.
Stocking density is one of the most impactful welfare variables in commercial pig production. At high densities, pigs cannot perform natural social navigation, resting, and exploratory behaviors. Competition for resources intensifies, and subordinate animals suffer chronic stress from inability to avoid dominant individuals. The relationship between density and welfare is dose-dependent, with welfare deteriorating measurably above optimal thresholds even when other parameters are well managed.