I ventelated mine up at the top of the wall between the roof boards so it is under the eaves.If by 'modified' you mean 'frozen to the floor', then yeah.
The chickens keep it just warm enough that if it gets up to 25*F or so the snow that blows inside will melt and get everything soaking wet. Of course, it's never warm enough to thaw it completely. Next year, I am going to build a pop door. And more window blocks. Screw ventilation, I'm tired of wet bedding. Also, I am building the ducks their own coop. See prior remark about bedding. At least this way those messy little things are only giving themselves worms, not the chickens too. They're lucky I love them so much...