The coop enclosure is fully enclosed (floor and roof), but when I let them out to free range, lowest part of fence is only 3' high split rail supplemented with chicken wire.
We have lost three chickens to predators this year. The first I thought was a fluke, but the last two have been taken in the daylight, in a fenced yard (granted a low fence), within an hour of being let out - like something is waiting. I think it's a fox or bobcat, since we have plenty of those...