We don't feed grain to our pigs.
≥80% of their diet is pasture. Fresh in the warm months, hay in the winter.
~7% of their diet is dairy, primarily whey. It's the local resource we have that provides protein.
After that is eggs, pumpkins, sunflowers, beets, turnips, sunchokes, apples, pears all seasonally as we have them from our farm.
We also get a little spent barley (good protein, fiber and minerals, no energy) from a local brew pub and occasionally a little bread for training.
We've been doing that for almost 13 years and have about 400 pigs out on pasture - we deliver weekly fresh pork to area stores and restaurants.
Genetics of the pigs matters. Select for those who pasture well, those who do well in your climate and management system.
Quality pasture matters. Plant it up with good forages.
Alfalfa's great - I wish I could get that as winter hay.
Managed rotational grazing is key.
See:
http://SugarMtnFarm.com/pigs for more about the diet we use.
-Walter
in Vermont