I was looking at Johnny's Selected Seeds, cover crops (green manure, biomass) last night. They actually sell a swine mix. "Laugh and Grow Fat Hog pasture mix. They also carry forage turnips, red and yellow mangels.Right now we have them on a 4-acre pasture, eating the native greens, grains and roots. We accent their diets with oats and corn (hog mash for sows when they are close to giving birth or breastfeeding). We will look into seeding the pasture with mangels, turnips, grains, etc. once they finish clearing the land of its goldenrod and scrub.
Eric