so I'm pretty new to duck ownership and this is my first cold night going down to the low 20's my ducks (2 mini call ducks who we adore) typically sleep in their pool (they have a small house which has their food so the food does not get wet and hay for them to nest in but they prefer to sleep in the water which never bothered me till I realized how cold it is outside tonight (and as winter really settles in we will have nights down in the single digets) I chased them out of the water once and got them in the house but left the door open and by the time I was back in the house they were back in the water. I could lock them in the house if they need that but they jsut seem so so much happier on the water but I dont want frozen or frost bitten ducks soooooo what do I do ps their run is preditor safe so I'm not worried about that factor just the cold cold cold.
Dump the water out? You could put new in the next day, it seems a bit wasteful, but if you used it to water house plants or in the greenhouse or something it wouldn't be that bad.
I think the ducks will figure it out if they start to freeze in place, but if not maybe you should look at getting different ducks.... a duck that won't get out of the freezing water and dies probably isn't the right duck for your system.
My first year as well. My solution is to not do a swimming pond over the winter. I am only going to fill their drinking water. I am carrying a fresh pail of water out to them every morning from inside. It will still be a nice deep water pail so they can dip their bills in but I am hoping it will give them fresh drinkable water everyday that they can drink for a while before it freezes (might be warm water) If that doesn't work I will try using a heated water bowl.
I am in the Pacific Northwest and we will have periodic cold weather. I have had ducks over the years here on the farm, (loved those Call ducks). In my experienced opinion you are on the right track. We kept the ducks in predator proof pens that had one end of the pen enclosed with plywood or a tarp. Face that enclosed end towards prevailing winds. Straw or shavings on the ground in the enclosed portion of pen. They will mess the bedding up a bit, a fresh layer over the top when needed. When the wading pool froze over we just left it like that and carried pails of water out to them. Get two pails, it was much easier to just switch pails out in the morning, removing the frozen remnant pail and dropping off the new water pail. We also found out that feeding cracked corn or scratch during the cold weather seems to help. The understanding that we have is that the corn actually produces heat in the poultry as it ferments in their crops and gizzards. Whether it is true or not I know that all my poultry will eat far more scratch during the cold weather then hot weather. Now this next part is only if you are like totally going to "mother" your ducks. In the past, especially with young ducks in cold weather, we would run an extension cord out to the pen and put a clamp light with a heat lamp in it and turn it on at night. You can get a clamp light at any of the big box hardware stores along with a heat lamp. Clamp the light up high up in the enclosed end of the pen you don't really want to over do it with the heat lamp. A heat lamp really warms and with grown ducks you are only trying to "take the bite" out of the bitter cold.
I would like to confirm for you from Minnesota that your ducks will do fine in the cold, ducks are from the northern hemisphere and are covered in the down feathers we fill stuff with to keep us warm. My ducks don't blink an eye in the single didgets. I also got rid of the pool for winter and got a small black tub made for mixing concrete at the hardware store, it is easy to dump and fill each day and on the above freezing days there is enough room for them to get in and get clean! The black color also attracts the sun when it's out so keeps the water from freezing a little bit longer. My ducks don't seem to have a problem with a light coat of ice on the top either, they just break it with their beaks and start drinking, they seem to like drinking snow also!