Stocking density is one of the most fundamental determinants of pig welfare, and research clearly establishes the welfare costs of overcrowding even within legal limits.
Stocking density is a welfare variable where the law represents a floor, not a standard. Legal compliance does not equal welfare compliance — the minimum space allocations in most jurisdictions are significantly below what welfare science identifies as adequate for positive welfare. Pigs at legal minimum space allocations show elevated aggression, impaired lying behavior, and higher rates of injuries than pigs at higher welfare densities. Consumers, retailers, and certification schemes that demand higher welfare standards than legal minimums are the primary drivers of genuine welfare improvement in commercial pig production.