Rooting is one of the most strongly motivated natural behaviours in pigs, serving exploratory, foraging, and thermoregulatory functions. Providing substrates that satisfy rooting motivation is a fundamental welfare requirement that most conventional systems fail to meet.
Pigs deprived of rooting substrates redirect this powerful motivation toward pen fixtures, pen-mates' tails and ears, and stereotypic floor nosing. These redirected behaviours cause both social harm — injury to pen-mates — and self-harm through repetitive floor scraping on hard surfaces. The welfare case for providing adequate rooting substrate is one of the strongest in pig science: the behaviour is highly motivated, easy to satisfy with appropriate materials, and its provision produces measurable reductions in harmful redirected behaviours. The barrier to implementation is primarily economic — slurry management with straw requires different infrastructure than slatted floors. Premium welfare markets that price in this infrastructure cost are essential for mainstreaming straw-based systems.