Time and time again, we see posts here from frustrated folks who thought their coop and run was "predator-proof" and now they've lost one or more chickens to a mysterious predator. Oh my! How could they have gotten in?!? http://www.bearstudy.org/website/up...icnic-slinky-mink-update-january-31-2017.html I don't care about the bear stuff in that link, so scroll down to the bottom of the page and watch a mink (which is usually larger than a weasel, at least here in the U.S.) scamper right through a one-inch (2.5 cm) gap. I mean seriously, did it look like he had any trouble? None at all. So think about that when you look at your own coop with an eye to make it safe for your birds. A one-inch gap is more than enough for a predator who can easily kill your chickens to get into a coop.