I am lucky, or I guess my chickens are the lucky ones, Here in Sparks Nevada it really doesn't get that low in the winter. I have ladies that like to roost outside. So it's a good thing that it doesn't get really cold. 5 is the lowest that it's gotten so far this winter, and it rarely gets...
I have two White Leghorns in Sparks Nevada. It has already been 19 degrees and I have not had to do anything to the combs on my ladies. They sleep outside on the outer Roost (don't know how smart that is but...) I do not have supplemental heat or lights, I do nave a base heater for my Galvanized...