The minimum space allowance required for pigs in transit at a broad range of body sizes has not yet been adequately assessed or well described. Consultation between the swine transportation industry, animal welfare groups, and a literature review produced a maximal loading pressure recommendation for pigs weighing from 5 to 250 kg body weight. Under ideal conditions, the recommended maximal loading pressure for swine loaded in groups can be described as a hoerl model y = (37.53)(0.9969)W(W0.5008), where y = loading pressure in kg body weight/m2 and W = average animal body weight in kilograms.