I thought about it once so I looked in to it, but the more I looked into it, the more I realized they may not be my best choice on my farm at this time. Maybe if I didn't have deer I would raise them.
I read they are very capable of running through a barb wire fence when they get agitated. They take months to adapt to a new farm, and until they do, they can be difficult to keep inside the pen. They are good at escaping. I am sure there are many good things, but they are not like cattle. They are more wild, so the fencing should be extra heavy duty. I don't wanna discourage you, just giving you a heads up. As with any livestock, the more research you do before you get them, the better prepared you will be to care for them.
At one time I saw ads for them on pennswoods and Craigslist. Also if you google bison farms in PA, there are some websites with contact numbers. Good luck, have fun and let us know if you find some.