I have 2 cats who coexist with the flock, one is a bit older and thinks she is a chicken, she even gets in the brooder and has naps with chicks without harming one of them, however they don't feel the same way about her and huddle in a corner. She free ranges with the chickens all day and they don't seem to mind one bit, they have seen enough of her to know she isn't a threat. She has also made a few attempts to sit on eggs I had stashed for incubating, I came in the room and there she was gently placing all 20 lbs of herself carefully over the eggs, once she was situated she laid down on them purring away. The younger one I would never trust with chicks but the adults would kill the poor thing if he tried to get fiesty.