A friend and I caught 2, 2 star boars before the patch and bred them, and we fed them Mushrooms & Berries, and they ate that & tamed eventually. You can also feed them either Carrots or Turnips if you have them unlocked.

With the fence, I didn't bother building one, or a pen really but rather found it easier to just dig a pit somewhere near my house and lure them into it. (Haven't tested it after the new update yet but will see if there is any difference)