Here in Michigan the temps are about the same at night but we know it is going to change as we near the winter months. Our egg production is unbelievable right now and at a peak. Based on pro and con articles, I insulated only the ceiling in my coop. I have closed off my exterior windows at night but leave an exit and entry chute open. I have noticed my girls have turned their backsides facing away from the chute door and drafts at night while perching on their roosting boards and poles. A sure sign telling me I need to close those up as well. I have sufficient ventilation so I would assume they will be fine. No severe molting as yet, but I can tell some winter feathers are filling in their coats and buff. Put on your hat, your boots, your muff and gloves and snuggle up to those you love! Stay warm girls!