You could put 12x12 pavers. The critters that show up in yards, even in town is amazing. We lived in Bradenton, FL, and I saw coons and possums at night a lot. There are almost always rats in the city, and cats and dogs, owls, hawks, the list of varmints that wants to eat your chickens is long. Even snakes will eat small chickens and eggs. It's a jungle out there. I love my chickens too, and when I saw a hawk flying away with my young polish pullet, my heart broke. She was still screaming. I thought it was ok to let them out of the tractor to play in the grass. They stayed within 6 feet of the door, but the hawk was too fast. I keep working to make my coops more secure , and even go back to check existing coops for gaps. If you turn on a light inside your coop at night, you will see where the gaps are. Coons will reach into small gaps and grab any part they can reach of a chicken and chew it off. Thanks to that, I had a one legged chicken for a while. I think she died of sadness because she could no longer run and play. My friend lost 20plus chickens in one night to coons, they just kept reaching in and grabbing. Sometimes they just eat the heads. It's horrible. Hope you don't have to experience it:'(