Pigs have a powerful drive to root and explore. Providing rooting substrate — straw, compost, peat, or silage — is one of the highest-impact, lowest-cost welfare improvements available in pig farming.
Pigs on bare concrete floors with nothing to root or explore develop redirected behaviours including tail biting, ear biting, and bar chewing. These are not behavioural problems — they are frustrated normal behaviours. Providing straw is inexpensive and dramatically reduces these welfare issues. The main barrier is that slurry systems cannot handle straw — requiring system redesign.