All comes down to how wet your winters are, not how cold. If your winter is divided between mud and bitter cold, feather footed breeds will be happier inside. I've traveled a bit, spending time outdoors in varied climates, and have been just as miserable in a coastal 40 degrees with near 100% humidity as in a dry negative 20. If not more so. Having ventilation options that you can change as the weather changes is handy, as is adding dry bedding. You want enough ventilation that their own respiration does not accumulate in the enclosure, but you might want to be able to restrict ventilation if there is a damp foggy mist in the air. Adding dry bedding at key times can help soak up some of the excess moisture in the air.
Here it is not uncommon to get a lot of rain and fog, get everything really damp, and then turn cold. The top four inches of dirt thaws out when the warm front comes through dumping rain, and then it freezes back when the high comes through and turns it back cold. Muddy soup sets on top of an ice block until spring. Feather footed chickens allowed outdoors can end up with frozen mud bricks encasing their feet. If allowed outdoors, those areas have to be bedded as well, but they will scratch down through it to play in the mud on the warm day that comes before the 4 inches of rain that turns to snow followed by teens. The best thing I came up with when I had feather footed breeds was to put carpet remnants in loafing areas, and then put bedding on top of that. The carpet had gravel underneath, and allowed the rain to pass through.
