Doesn't the coop have a pop door? If the pop door is closed at night, there will be no drafts, and if it's open during the day but the chickens are outside, drafts in the coop during the day would be irrelevant. Also, drafts only matter if they are at roost level, or if they bring moisture in from rain/snow blowing through the pop door. If the roost is above the level of the pop door (as it should), drafts from the pop door won't get to the chickens. The dangerous kind of draft is one that ruffles the chickens' feathers and breaks the insulation that they provide. Air moving below or above the roost is not a problem. The goal isn't to keep the coop warm, but to keep it dry. If the coop has enough open ventilation (as it should), at the top (as it should), then warm air will escape through it and the inside and outside temperature will be pretty much the same. Which is fine, as long as the coop is dry and wind isn't blowing directly on the chickens and breaking their feather seal.Yes, run is predator proof. Vinyl flaps will be to keep out winter drafts.