Hello, and welcome to BYC.
Great advice from DL.
Hello and welcome to BYC! Glad you joined.
You do not need to heat the coop. That actually causes more harm than good. However, you need a properly sized, dry and well ventilated coop for cold winters. If the WLHs are getting their combs pecked, you may have a sizing problem with your coop and run. You should shoot for at least 4 sq feet per bird in the coop and 12 in the run for winters.
IMO, runs in the north should have a solid roof on them to offer a snow free space during the day and should be constructed such that it can be winterized with tarps to block blowing wind.
I use poultry netting powered with a 10,000 volt charger around my entire setup. That has kept everything from the neighbor's rotten dogs to the resident momma black bear at bay. If anything makes it through that, they have to get through the 1/2" hardware cloth I have covering everything to access the coop/run combo. I've had one hawk strike and see them multiple times daily but have never had any bird so much as injured by a hawk. The flock as lots of cover in their pen.
Great advice from DL.