Our pastures provide the vast majority of our pig's feed and we don't buy or feed commercial / grain based feeds. We have around four hundred pigs on pasture in northern Vermont. Our difference in climate from you will make a big difference in species selection for forages. We grow a lot of brassicas, cole crops, out in our pastures such as kale, rape, turnips, etc.
Clovers, including red clover, are a wonderful part of the species mix. They suck down free nitrogen fertilizer from the sky and improve the soils. We also have a wide variety of different grass species and millet out in our fields. Diversity is good. We have seeded in many species of clovers as well as other legumes like alfalfa. The red clover establishes quickly. Legumes are a bit particular about soil pH, liking the more neutral soil. Our soils started out very acidic but have been improving through the grazing. The animal manure and
urine is fertilizing and improving the soil.
For us corn is not a good choice but I would grow it if I could. Our land is too thin, rocky, sloping and our growing season is short. It seems that five out of seven years our corn fails.
Sunflowers, sunchokes, mangels, beets, radishes and pumpkins are things we grow a lot of in our winter paddocks - areas of high fertility. These make good fall and food for the livestock.
We buy in winter
hay which is a good source of imported nutrients for us, on top of what the plants are sucking down for
CO2 and N from the sky.
See:
http://SugarMtnFarm.com/pigs for more about our pigs's diet and how we do things.
Cheers,
-Walter
in Vermont