Recent trends in pig housing.
D000383:Agriculture; D000818:Animals; D001947:Breeding; D003441:Crowding; D004777:Environment; D006798:Housing; D006801:Humans; D008460:Meat; D013315:Stress, Psychological / Q000517:prevention & control; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control; D014691:Ventilation