One day, a couple months ago, I couldn't find one of my hens. She wasn't roosting with the others, and not in her run. I thought "I'll find her in the morning." I woke up to a screaming hen running around like crazy. I guess she snuck in the window when i wasn't looking, and she roosted on the fireplace mantle! She even layed an egg up there! I almost died of laughter, before I caught her and put her with the others.