Providing rooting substrate such as straw, compost, or peat is a high-impact welfare intervention for farm pigs, satisfying one of their most strongly motivated natural behaviours.
The welfare benefit of rooting substrate for pigs is one of the most robustly demonstrated findings in farm animal welfare science. Without substrate, pigs redirect foraging motivation toward pen-mates, causing ear-biting, tail-biting, and aggression that creates both the aggressor and victim welfare harms. Straw-bedded systems show dramatically lower rates of these injurious behaviours. The welfare case for rooting material provision is so strong that its absence in barren slatted systems represents a fundamental welfare deficit regardless of other management factors.