At most of the 550 U.S. hog farms growing for Niman Ranch, hogs are likely foraging outdoors on about 20 percent of the farm. Fields making up another fifth of the farm are likely growing corn, nourished by the manure left behind from the hogs that lived there last year, while another fifth is growing soybeans. Each of the last two-fifths is probably growing any number of produce crops — or simply left uncultivated.
Next year, everything will shift. The hogs will forage on a different field, the corn will grow on another and so on.