Ventilating for extreme cold

[AK Michelle]

H2B is concerned that venting interior air into the channels between the ceiling and the roof will cause hot spots and lead to ice damming. So now he is thinking to put vents through the walls some high and some low. I worry that the lower vents will be low enough the chickens will get drafty.

Anyone know how much air exchange we need in an 800 sq ft coop? We are talking winter, for ventilation, not for cooling in the summer, we got that covered. This is to allow for fresh air exchange during the super cold winter months.

Thanks everyone for your input.