oh! also, giving them higher protien & high fat treats and along with a handfull of scratch every day during the winter gives them the energy they need to keep themselves warm
just a bit of advice.
for high protien/fat treats you can give them some bacon grease, or just about any leftovers from lunch, dinner, etc.
Thanks for the great respones. I knew this forum would be a great one and I can see now I was right. I will probably go ahead and keep them somewhat heated in winter. I had been stressing about this but no more. Thanks for such great answers.