How much food dose a sow eat in a year?

in commercial operations they are fed a mixture of grains. in the wild they will eat practically anything. they have very keen noses and can find things growing underground like roots,veggies, etc. they are used in England to find truffles growing under the ground, a prized delicacy. sows on occasion have been known to eat their young, as they will other small rodent sized critters if they can catch them. even snakes. hogs are immune to snake venom.