fence and good hot wire keeps them in
They will go right through if they want out or in. I've seen them run straight through 5 strand barb wire fences like they are not there. They put their nose under the bottom wire and just run through them. If the wire is too tight for them to go under I've seen them break them. Also we grow watermelons and have a hot wire around them and they will just squeal and go right on through it. On our traps we've had them break more than 17 welds on cattle panels and escape. You might keep them in for awhile but if the decide they don't want to be there they will find a way out.