Thank you for your comment. We built our coop with plenty of ventilation so I'm thinking we should be OK. I was thinking of maybe just doing the ceiling so the cold from the snow doesn't radiate so much and that will also help with summer heat....do you think that might help a little?
I am thinking of just insulating my coop's ceiling also, but I have went through 2 winters with my flock in an uninsulated coop with only a 75W and 50W red light bulb and water heater for heat, and have had no losses due to cold. The rooster's comb and a couple of the hens got nipped a little bit, but the hens did not stop laying. I have a temperature sensor in the coop and I think the coldest it ever got in there was -22 F., for a short period. The chicken's body heat keeps the temp in there about 10 degrees above ambient, even with good ventilation and no insulation. I do reduce ventillation in the winter, but not to the point where I get condensation. Snow on the roof of your coop will actually act like insulation. I never get any snow on my coop's roof because it is under my deck. I think you will be fine without insulation. The hardest thing for me about winter is keeping the water from freezing, but my waterer base heater does a good job of keeping my 5 gallon galvanized steel waterer from freezing up, even if it gets to 30 below or colder. It also adds a little heat to the coop. I have a long extension cord run out there but maybe someday I will run conduit and wire. The water heater only comes on when it gets below 40, and I have my red bulbs on timers so they only come on in the early morning hours. It seems this setup raises my electric bill about $10 per month in the winter. Hope this helps!