happy duck
Crazy duck mom
You said it all!Mine don't care how cold it is They will swim. That part is mostly up to you wether or not you want to deal with freezing water and such. Personally I found it easier to just do away with swimming water during long periods of freezing weather.
But the first year I had just two call ducks I used a bird bath heater to keep their pool open all winter and it didn't hurt them one bit. No frostbite or anything. .but they did have a dry house to go get in whenever they got too cold.
I believe the consensus from what I've read around here is that as long as you provide a dry place where they can get out of the wind they should fine.
Maybe you could use some plastic sheeting or clear shower curtains to put around just part of your run?