Although pigs do not dustbathe like poultry, rooting in dry substrates serves analogous motivational functions that commercial housing systems frequently fail to provide.
Rooting is one of the most strongly motivated behaviours in pigs — they root even on bare concrete when no substrate is available, demonstrating the drive's independence from external reward. The frustration of being unable to express this behaviour in barren environments contributes to redirected aggression, tail biting and psychological distress. Providing even small quantities of rooting substrate — straw, peat, compost — dramatically reduces these behaviours. The relative ease and low cost of providing rooting materials makes the failure to do so on welfare grounds difficult to justify.