Alaskan Winter Ducks

[akhatchling]

I have 2 ducklings my kids are raising this summer and want to know if there is anyone else in Alaska or other region that has very cold winters like here that could give advice on wintering a couple ducks. I have 4 chickens in a coop my husband built but I don't want the ducks in there with the chickens. Any ideas? Do they need to have water to swim in? What temperature do I take the swimming water away??? I'm just full of questions!