4 hens here and only 3 weeks into it but this is the second time my youngest (lightest) "flew the coop". I'm think she either fluttered onto the coop then fluttered onto the fence and jumped into my yard. Last time she went into the neighbors yard... I think I have to enclose the top this weekend... ugh. Was hoping not to do that. Hopefully it wasn't a cat that chased her around... she seemed normal and looked fine. She was waiting at the run door when I got home..