I agree with everyone that a heated perch is unnecessary. I live near Lake Erie and we get some cold blasts from up north. I do get a good amount of wet snow, sleet, and freezing rain as well.
I have Polish Bantams that have no problems. My Guineas walk around in the snow and it doesn't phase them. Domestic Guineas aren't much different than their wild counterparts from Africa. The only time my Guineas stay in the coop is when it is snowing heavily, but when the snow stops they walk right on top the foot of snow. You would think that being a heat-loving bird they would not be adapted to the cold, but they don't seem to be bothered and I've never had a problem with frostbite.
I have Polish Bantams that have no problems. My Guineas walk around in the snow and it doesn't phase them. Domestic Guineas aren't much different than their wild counterparts from Africa. The only time my Guineas stay in the coop is when it is snowing heavily, but when the snow stops they walk right on top the foot of snow. You would think that being a heat-loving bird they would not be adapted to the cold, but they don't seem to be bothered and I've never had a problem with frostbite.