We have a herd of 30 sows plus boars. Our total herd including growers and all is about 100 pigs. Pastured pigs are our main farming product. We sell the piglets as well as finished pigs direct to consumers. People are very interested in higher quality, naturally raised, free range, healthy meat for their families. See my blog at
http://SugarMtnFarm.com/blog and look in the right sidebar for the Favorite Articles for discussion of how we do things.
Where are you located? We're in northern central Vermont where it is fairly cold. Pigs are hardy and do well just about anywhere. The big thing is providing them with shelter from the wind/rain (in winter), plenty of hay in the winter, shade in the summer
You can raise them just on pasture with no other feed, I've done it for three groups, but they will grow slower (7 months or so to slaughter vs 6). If you add other feed they grow faster. We feed excess milk, organic goats milk whey and cheese trim. The dairy makes the meat and fat of the pigs taste sweeter - delicious! We also grow a small amount of crops like pumpkins for the pigs to eat in the late fall when the pastures are used up. In the winter we feed hay. A full size sow or boar eats about 800 lbs of hay over the winter.
As to predators, we have lots but we also have large livestock guardian / herd dogs. They eat predators, literally. I would not try and farmstead without dogs. They are our partners, protecting the livestock, terminating pests, alerting us to strangers, cleaning up after slaughter and sharing in the harvest.
Check out
http://groups.yahoo.com/group/PasturedPigs/ for a excellent discussion list about pastured pigs. Greg Gunthorp who does it in a big way is on that list.
