I spent a weekend in the Bells Center Unit/Gays Mills last summer. Followed definite spoor for a sow and pigglets. She was a big one, her bed a bit over 5 feet long. Slept under the stars and through the night heard them rooting.
It was the first time there and looking forward to going back. Beautiful area. Come to find out I have family in the area and they told me a neighbor of theirs had taken out a pig with a car a few months later.
As to licensing, a small game license is required to harvest the pig for consumption, however if you give the game to the DNR for testing, a license is not required. At least that was last years rules.
Bells Center Unit has some nasty, swampy terrain; thick with the kind of foliage a dog won't even go into...perfect home for bacon.