As someone mentioned 'condensation'... Ventilation.. If your coup is so buttoned up as it appears what I can see, that tarp for instance is fine on the roof, not the sides. Unless they are wide open.. I live in a Great Lakes State and might as well be Alaska.. and Alaskans have so said. My coup is loosely buttoned up in winter. I drop or assemble loosely fiting windows over major opennings. Just to cut down on direct wind.. and close the big door which is left open in the good weather. Which contains a small open door for them to come and go.. It's no place I'd like to live, but the chickens thrive, and if I needed. It is warmer in there even with all the holes.