Greetings from another Michigander (Michi-hen). This is the nicest forum I've ever been on. If you have any questions, just ask! Someone will have an answer or suggestion.
Hello and welcome to BYC! So glad that you joined us here. I have learned so much. As far as your chickens- they are near enough full-grown that they don't need provided heat. But a dry coop should be enough- although check on them regularly. Have fun raising chickens!