When my chick's were little and I first moved them outside, I was worried about outdoor house cats at night. (That is my only real predator concern. I am lucky too!) You might be wise to look at bringing them in at night if you can't lock them up. I guess you could put the cage they were in inside outside and lock them in after dark. No cats bother my grown chickens, but I have seen bird feathers that indicated a dove may have been caught be a cat. My mother, who has been in this area longer than I says anything smaller than a pigeon needs to watch out for cats. That said, my mothers house doesn't have any fences or coups and hens have raised little ones in her yard. (The were volunteer arrival hens, not planned ones.)
