I have three Runners. Later this week the night temp is supposed to go down to -22 F. Their shelter is 4x4, plywood, uninsulated with shavings bed. This is their second winter but temps have not been that low before. Will they be OK? I could put them in chicken coop for the night (insulated house with heat lamp) but they are not used to being with the chickens so that might not be a good idea. I did read the long post on ducks in winter, and it seems clear that ducks can tolerate pretty cold temps. Just not sure how cold is TOO cold. Have had chickens for years, but fairly new to ducks. Thanks!!!