I like the web cam idea
They need to be able to wash their little heads, you are right. Did you see Tweetysvoice watering station? There are others with great ideas, too. But somehow the ducklings need to have water to wash their heads, and water to drink 24/7 until they're several (I feel...
Welcome to ducks!
Keep the littles separate from the bigger ones or they will be at risk of serious injury. Ducks do not tend to play nice, so the smaller ones need to be able to grow up a bit before they can be left together. It's a process, but it works.
Ducks and chickens sometimes do...