Space allowances for farmed pigs directly determine whether they can express normal social behaviors. Research consistently shows that current minimum legal requirements are insufficient for good welfare.
Pig stocking density is a welfare parameter with the clearest evidence base of any pig housing factor. The dose-response relationship between space and welfare is well-established - more space produces better welfare outcomes in a predictable, measurable way. Current minimum legal requirements were set with economic constraints rather than welfare science as the primary determinant. The welfare standard would set space allowances based on the minimum needed for full behavioral expression including simultaneous lying, social interaction, and movement. The transition from current minimum standards to welfare-appropriate standards requires both regulatory change and market mechanisms that reward producers for providing better conditions.