Hi folks. Just joined a few minutes ago. I am ordering 25 Australorp chicks. I am building a 10foot by 12 foot heated coop(I live in Northwest Indiana) with a 20 foot by 30 foot run. I have the design all worked out, but I have one question. I plan on an egress for the girls 9 inches wide by 12 inches tall. Do you think chickens would use a doggy door if I installed one in the coop? I would like to keep as much heat in as possible, but I am not sure if they would learn to use a doggy door or if I would just have to go with an opening of 9 X 12. Anyone have any ideas, I'd love to hear from you.