Over the Winter time all of our poultry is tucked away in sheds, it is just to cold here in Manitoba to let them run loose. We learned that lesson the first year of keeping ducks. We let them decide when they came in and out and sadly it soon became apparent that they did not make good choices, we lost most of them to cold exposure that first year. We felt terrible.
It can be tricky to gauge when it is too cold to let poultry out. It depends on breed, hardiness, is it windy, is it too snowy. There is lots to think about. My turkeys will go out up to about minus 10 actual temperature, chickens the same, ducks, no way!
The decision on whether they come out or not is now ours, and many owners differ on when it is fine for them to wander outside. Today all my turkeys, chickens and ducks are out (although not my Muscovy Ducks, who hate the slightest cold) We had fresh snow last night, it is currently minus 4 with a windchill of minus 9.
If it is way too cold for you, it will likely be way to cold for them. If it is cold but you can stay out comfortably the chances are they could to. Use your common sense as they lack it. Remember that your bad judgement can sadly be fatal to our feathered friends.