I'm having the same problem. This morning I brought out a waterer with fresh water from indoors and set it up in the run. By the time I'd finished chicken chores and indoor bird chores (about an hour), the water had iced over. The indoor waterer is also developing ice crystals down at floor level. If I use warm/hot water, it takes a bit longer for it to freeze up.
On the positive side, we'll only have to deal with this for a couple of days. It's supposed to be back to normal with daytime temps in the 50's by Sunday. I really sympathise with you northern chicken keepers having to deal with cold routinely.