I dug down and out away from my pen about a foot along the outside and put chicken wire down, then covered it with the dirt and grass. I also put landscape timbers along the bottom of the pen, where the wired goes into the ground. Knock on wood, I've not had any visitors yet trying to get into the coop. But my neighbor's dog (he adopted me and now stays in my FENCED yard...yes, he jumps the 4 foot fence and hangs out over here!!!) and my parent's dog (he has full run of my yard and the field and my parents yard) help keep any wildlife out of the yard. Skippy performs patrols all night and Toby does the daytime rounds. They don't try to get my chickas mainly because when I first put my babies in their coop and pen, I made sure the dogs knew they were not food for them. I hope your girls do ok!