Might want to add fly rafters over gable ends and to protect some gable vents.@aart
Ya the framing will be built to handle the snow. I plan on putting 1/2" plywood over the framing as well. The soffits are going to be completely open (with hardware cloth covering openings) for additional venting. I have read on here that running open soffit and a ridge vent are the most optimal setup for chicken coop ventilation. Feel free to correct me if I'm wrong.
Ridge vents might help a bit in summer but once covered with snow they won't do much.