I agree with not heating the coop. I live in Central IL, so our winters do tend to be ever so slightly milder than what you'll be getting in Northern IN but not significantly. I do not heat my coop (although they do have an insulating air pocket between the outside wall and the inside wall as well as a 4" air pocket in the floor which is then covered with deep litter) and have not had any problems at all with my chickens in cold weather. The girls in their second or later winters don't lay hardly at all after their fall molt until the days start getting longer in February or so. But all of my pullets in their first year of laying have laid just as reliably during the cold winter months without supplemental heat as they do during the rest of the year. I remember my first year having chickens I would leave them locked in the coop until closer to noon on days that I considered "really cold." One morning I decided it was just "too cold" for the girls and as much as they hated it, they would have to stay shut in all morning. Except when I went out to check on their water around 8, every single one of them met me at the gate to the run. I had forgotten to shut the coop the night before, and the girls had all been out in the run all morning. Clearly, their definition of "too cold" was not the same as mine! After that, I stopped worrying about the cold and just let them be chickens. Granted, until we got a roof over our run this past year I still had to go out and shovel the run when it snowed or they would refuse to come outside. And I still spread a thick layer of straw in the run in the winter. I think it helps keep their feet from getting too cold, plus it gives them something to scratch through when it's snowy and they don't feel like venturing outside of the run.