I lock mine up at night. I used to leave it open but finding large canine prints in the first snow last fall circling their pen scared the doodoo out of me. If we had electric fencing I might chance it but we don't. We have had coyotes and stray dogs in the past and lost a lot of our freerange chickens to fox. When we move to a bigger place I will be looking into getting a herd guardian of some sort but that's a few years off.