I think I glimpsed a conversation from you about living on a hill side surrounded by woods. The internet cut off then so I lost the conversation but that is just what we have here.

We have lost all of our free ranging chickens so far to various kinds of predators. I sadly gave in and locked Lee in her house and small run only to find this snake, an internal predator.
Today I heard her squawking and went out to find a groundhog standing up in the corner of her run. It was, no doubt, only interested in the surrounding gardens but it sure did scare Lee.
Sometimes she just makes a lot of noise because she has trained me to come out and check on her and bring snacks but she does have a distinctive squawk when she is in danger or afraid.

Our KittyKate protects us from all kinds of rodents. The day I found the snake she sat on top of the outside of the nesting box for a while, preying.

Even though I think our chicken house is secure when you get one make sure it is very secure with a long covered run.
I have loved all my chickens and plan to get more next spring but there is so much danger living in an isolated place.