[Pig fattening: Large group housing belongs to the future]

ammonia ammoniac animal husbandry methods animal welfare behaviour bienestar animal caillebotis cama (animales) cerdo comportamiento comportement efficiency eficacia engorde engraissement excretion fattening group size horas laborables litter for animals pollution by agriculture pollution par l'agriculture porcin slatted floors suelo emparrillado swine taille du groupe temps de travail working hours