If you have nuisance rats outdoors, use poison-free baits like RatX that include corn gluten meal or cob. Rats cannot digest corn, so it dehydrates them and eventually they die. There is no secondary poisoning risk for birds of prey, people, or pets.
Put cayenne pepper in the feed it's good for your chickens and they are not bothered by it but it will deter the rats. Good luck hope you get to keep your babies ❤️