Rooting is one of pigs' most strongly motivated natural behaviours - providing appropriate substrate is fundamental to welfare and is required by all serious welfare standards.
Rooting substrate welfare is one of the clearest evidence-based welfare requirements for pigs. The motivational strength of rooting - demonstrated through barrier tests showing pigs will work very hard to access substrate - indicates high welfare significance when deprived. Pigs on bare concrete redirect rooting toward pen fittings and pen mates, causing social problems and injuries. Substrate provision addresses the rooting motivation while also providing occupation that reduces injurious behaviours. The welfare standard is clear: permanent access to manipulable rooting material is not optional enrichment but a fundamental welfare requirement. Enforcement of existing UK law would significantly improve pig welfare outcomes.