feathers not waterproof????

My muscovey hen just had 20 little quackers
the drake looks rough like there is somthing wrong with his feathers any ideas?
planning on building a floating island for top swale to share the love im thinking tractor tube as floatation

It could be that he is getting ready to moult. I know some of ours in the spring look terrible until all the new feathers come in. And yes feathers are not waterproof on their own. It's only when the waterfowl have "built up" a layer of oil on the feathers that they truly become waterproof. We purchased some muscovies from a bad situation and they were absolutely disgusting and it was a few weeks of them being here free range and getting cleaned up before they stopped sinking up to their shoulders in the pond! LOL!! now they are just fine and float up top like normal ducks.

This also happened to one of my drakes when coyotes got into my fence during an ice storm. They nabbed a few ducks and seriously injured two drakes. One didn't survive, but the second looked awful every time he got wet for the next bit. Eventually he got back to his shiny self though after a few weeks. One possibility is due to some severe stress like that, but more than likely Misty is right about the molting.

baby ducks are NOT waterproof
their oil glands take a bit to develop, when they are raised by mom, they can swim and play in the water, because mom will preen her own oil gland and then preen her babies- giving them waterproof protection from herself till their own glands catch up
if they are not raised with mom- they can not waterproof themselves

if they are being raised by mom (it sounds like they are) maybe he was being a stinker and missed his mom preening time?
how old are we talking here?