My coop is way undersized for my flock (9 birds in 20 sq. ft.) When I bought them as chicks they fit.... This winter they refused to step out into the snow. They stayed in the coop all day, pooped all over in it and started pecking each other. I had to expand their space somehow. I had dog kennel panels that my dog outgrew and a 10' piece of metal roof left over from a construction site. I found a 10' 4x4 buried in my yard, and I bought a roll of 6mil poly film. Here's what I made. The panels are 3'x3' and I had 8, making a 3'x9' pen. I put the 4x4 down the center to hold up the roof and put plastic over the whole thing, using concrete curbs (found those in our junk pile in the yard too) to hold the plastic down. DH thought I was nuts when he saw me putting this together. I thought he was right when they wouldn't go in for nearly two weeks. I finally got fed up and grabbed one of my girls, (the black one) and tossed her in with a cup of scratch. Once the girls figured out that it wasn't an oven and she was getting treats, they ALL went in. Now they rush out of the coop every morning to go in and roost, scratch and sit in the sunlight. I think this spring I will attempt one made from cattle panels, 1/2" wire mesh, bubble wrap and greenhouse poly. For such a simple concept, I must say that it stays very comfortable in there for them. I'd let them sleep all night in there, but as you can see, it's not very predator proof. A weasel can walk right through those spaces. Amazing what can be rigged up with yard clutter!