Chickygirl2, your birds are beautiful too!! My garage is fairly air tight but I had planned to leave the side door open this winter - when it's not TOO cold - so they could still get to the yard. I do have my quail hutches that I could keep them in for the winter though...hmmm...wheels are turning!!! In the garage, plastic sheeting like Chicky's pics...might have a winner!!!!
My two Mille's didn't suffer any frostbite last year and we had severely cold temps. at times. There were a few mornings with temps. at -5 and then during the day we wouldn't get out of the 10 degree range. My rooster and hen made it through just fine! I think the biggest key is to make sure the coop you have them in is draft free and dry. Those two factors make a world of difference when it comes to having chickens in freezing temperatures.