I would love to find a pig that could turn compost piles like Salatin's do (pigerators), graze brush in the summer (Shepard's pigs with nose rings), fatten up on woodlots, and keep outside in the winter (Holzer) ... is there a perfect pig breed
You're looking at the wrong end of the stick.
There is no perfect pig and there is no best breed.
Rather there are many excellent ones.
The line within the breed can be far more important than the breed itself. Pigs have been selectively bred, within breeds, for basically three groups of traits: show, confinement and pasture. The best way to get a pig that does what you want is to get it from someone who has been raising pigs that way for the purpose you want for a while and it might be one of many breeds or a cross. See:
and from there also read the linked articles.
We use Yorkshire, Berkshire, Large Black and Tamworth predominantly in our genetics. I have a total of nine genetic lines between about four hundred pigs out on our pastures. Pigs have wonderfully plastic genetics and reproduce quickly and in great numbers making them very easy to selectively breed to fit a situation. Have clear goals in mind and work towards them.
It is not the pig but the management that makes the difference. If you want them to root then put them on an area longer. If you want them to graze then rotate them. See:
I have repeatedly measured grazing rates and find that our pigs graze 23 sq-ft per hundred weight of pig per day. This works out to be about 10 pigs per acre MAX for sustainable grazing based on no supplemental feeds and good pasture. Speaking of which - plant your pasture up with legumes, soft grasses, chicory, amaranth, brassicas, etc. These will work well in your climate too. I do mob, frost and storm seeding. See: http://sugarmtnfarm.com/2010/09/15/frost-seeding/
and feed a steady stream of food leftovers from the local high school.
Bad idea. You do not want to be feeding post-consumer wastes to pigs as that is an excellent way to give the pigs disease and get fined by the government. In some locals you are allowed to feed post-consumer wastes provided you render or boil it. That's a lot of work and energy. There is still the problem of forks, knives, razors, plastic gloves and other items in the waste stream that will kill some of your pigs. I recommend not doing it. Stick with pre-consumer wastes.
We have an arrangement with a local butter and cheese maker - we handle the disposal of their liquid whey. They're small enough that it is not worth investing in the multi-million dollar equipment to dry the whey for sale so they deliver it to us and we feed it to our pigs, about 1,800 gallons a day or so. This makes up about 7%DMI of our pig's diet providing lysine. We have a similar arrangement with a local brewery for their spent barley which makes up about 2%DMI of our pig's diet. This keeps the materials out of the waste stream and saves them money. About 80%DMI of our pigs's diet is pasture/hay and then the rest is apples, pears, pumpkins, beets, turnips, eggs, etc. See:
feral population that would destroy the landscape.
Good fences make good neighbors. -R. Frost
if one were to put nose rings in
Ringing is not necessary. See the above article about rotational grazing and rooting.
I'd love to have a hardy pig that would require minimal care in the winter
Selectively breed for it. It takes time. Get starting stock from someone already doing it. But your first year or two raise feeder pigs over the easy warm season. Don't start thinking about breeders yet. Ease your way into the mud.
Our pigs are very hairy. Part of that is environmental. Part of that is genetic selection. This helps.
A pig that can put weight on from a lean diet, like pasture, helps a lot. Lardier genetics help with this but too much can sacrifice speed of growth, which matters even more for those of us in the northern climates. I want pigs to get to slaughter weight within eight to nine months. Boars from our best line (Mainline) get to slaughter weight (250 lb LW) in about six months over the easy warm months of summer. Add a month for gilts. Add a month for slower breeds. Add two or three months for fall pigs going over the winter. Boost the calories if you can in the winter. We use hay to replace pasture over winter (see: https://www.google.com/search?client=safari&rls=en&q=site:sugarmtnfarm.com+hay&ie=UTF-8&oe=UTF-
but hay is not nearly as good as fresh pasture. Alfalfa is great stuff if you can get it.
Our climate is similar to yours. We're in USDA Zone 3 in the central mountains of northern Vermont. We typically get about 14 to 20 feet of snow which packs to about 4' and it gets down to -45°F some years, -25°F or lower every year. Wind protection is key. A deep bedding pack that composts producing both food and heat is very helpful. Our Ark is helpful - an open ended hoop house building about 100'x40'. Selectively breeding for hardy winter pigs is key. That takes time, patience and persistence. It also takes numbers. I've raised and slaughtered many thousands of pigs over the decades. Breed the best of the best and eat the rest. I figure that 95% of females and 99.5% of males go to slaughter. Only the last small percentage, the top animals, get a chance to test breed and not all of those will get kept.
Be sure to read the older articles in this form as lots of people have had questions before, questions you might not even thing to ask yet...
Other valuable resources are: