AK Michelle,
It is wonderful to have chickens and think of them as mostly self sufficient, but we also have to remember that when we enclose or cage anything we then make ourselves responsible for their safety. If you are loosing combs and toes then your housing is not warm enough. You may consider insulating the house which is easy and can be cheap. But a heat source sounds like it is an absolute necessity in your area. Is the Chicken house close enough to run electric or is a small wood stove more practical? If you have land and access to fuel and a cheap used wood stove it would keep any building toasty warm for free. There are some ideas. Sometimes we adjust our lives to having chickens slowly and its ok to learn. In this case you will need to add some things for more than their comfort, it sounds like more for their survival. Frozen combs and toes are painful, sometimes a chicken with frostbite will quit eating, can get an infection and may at worst die. I'm not trying to scare you or scold you, its just that since this has already been a real experience for your chickens I'm sure you will want to spare them any more suffering! Thanks for your honesty and questions.
Andy in Fredericksburg