Yes the top of the area is uncovered. The fence is hardware cloth.
I guess I could see a predator possibly getting over a 5 foot fence but I don't see them being able to drag a chicken back over with them. I've yet to find a body or any parts excepts some feathers.
Thanks for the replies.
I let the ladies free range in the enclosed pen that I described and have a secure coop (haven't lost anyone at night yet at least).
The hole was very small under the fence where the feathers were found. Maybe 6" tall.
Ok I'm looking for a little bit of advice here. We recently had a number of chickens "disappeared". In all cases the disappearance occurs between about 8am and 5pm. I know the first couple were a fox (or ground predator) because i found the hole under the fence that had a bunch of feathers...