Weasels can climb, and dig, and go right through chicken wire. If you share space with a weasel population, you must use hardware cloth with holes that are less than 1" x 1".I've also heard that decapitation is a strong indicator of weasels, and that they can get in through quite small holes. Luckily we've been spared a weasel attack, and they don't seem to be in our immediate area, but I did try to plug all the 1" gaps. However, the upper parts of our coop are 2x4" mesh. Does anyone know whether weasels can climb fences or chicken wire?
You can catch a weasel in a trap if you're canny and bait with the carcass of the chicken they killed. Just beware, when you have one in a trap, they have a very stinky musk that is very hard to wash off. We shoot it while it's in the trap.