We're having a mice issue, thankfully not rats, and my wife is harping we get a cat...My fear is the cat will mistake a baby chick for a mouse, we just had one born and it fell from the nesting boxes to the floor of the coop and would have easily been a target, I think...Other than that, I think a good mouser would do us good, I just don't want issues with it and ducks and chickens that free range...