How much winterizing do you do?
I honestly didn't plan to even close their windows. They have 4" vents along the top of the wall, and a vent along the ridgeline, as well as vents at floor level in the sidewall.
Am I being overconfident?
I don't remember winterizing even in Virginia, and didn't lose birds to the cold (did have ducks freeze their breasts to the ice once though.