Put it under a heat lamp positioned so that it can move closer or farther from the heat at need and replace your water dish with a waterer that your ducklings can’t get into, but has water deep enough to allow them to fully dip their bills and keep their nares cleared out. Or, put it on a hot water bottle wrapped in a towel, or on a waterproof heating pad wrapped in a towel. The important thing is to get it warmed up and able to self-regulate the amount of heat it is getting and to keep it out of the water until it is fully feathered.
A shallow poultry waterer that looks like a plastic jar upended and screwed into a shallow dish worked well for us during early ducklinghood and was only a few dollars at the feed/farm store. You can also make a safe waterer from a gallon milk jug, thoroughly washed out, with smooth holes cut a couple of inches up from the bottom, large enough for the ducklings to stick their heads in to drink, but not large enough for them to climb into the waterer through. Just fill it to the bottom of the holes and add more through the top as needed. Quick, recyclable and virtually free. When your ducklings are fully feathered, they can distribute oil onto their feathers, but their current downy stage doesn’t let them stay dry in water and makes them susceptible to hypothermia. Their waterlogged down gets too heavy and they can’t get themselves out of the water.
I hope your little one recovers quickly and without further incident.
