Compared to other breeds Muscovies tend to be not as enthusiastic to get in the water, subsequently, they are more predisposed to developing feather problems associated with lack of water. Having a bird with an existing problem that discourages regular bathing can make matters much worse, so oftentimes it comes down to the owner's will to keep up hygiene practices.
In a normal situation, the feathers on the surrounding the duck would be well oiled with the oils that come from their preening gland (uropygial), located pygostyle on the duck - posterior to the ducks back. Almost all stimulation to distribute the oils across the feathers comes when the bird in water; when not in water very rarely do you see a duck distributing oils across its feathers. It's likely your bird has not been distributing the oils across its feathers so the microscopic interlocking barbules are not anymore interlocking which allows moisture penetration into the down.
Regaining oil distribution over the feathers consists of steadily introducing water back into the duck's daily life. During cold weather, letting the duck bathe in water can create hypothermic conditions; so instead, you may mist the duck's feather gently with a mister. During periods of warm days, letting the duck swim in water supervised would be good. A quick look at the bird's oil gland to ensure it's not clogged or infected may be a good idea. A warm compress to the oil glad can often be beneficial in getting it back up and "running".
Nutrition plays a key role in overall health, and feather development. For a bird her age, feeding an all flock feed, flock raiser, or Mazuri Waterfowl feed would be good. Access to greens, sunlight will also prove their usefulness in the long run. Whenever there is some sort of leg problem on one leg that creates more pressure on the opposing leg which increases the chance of conditions such as pododermatitis developing; you'll want to check the bottom of her foot pads every month or two to ensure there are no sores of any kind devloping.
it’s a her! And I carry her outside to sit in the grass next to her pool, feed and water dish. I am going to be getting her some better food today and I’m looking at getting her a friend. I’ll have to look up where this oil gland is located. And I was considering buying her a brace for her leg? Thoughts on that? She’s a lot to take on now just because I don’t know much about Ducks and I’m trying to bring her back to best that she can be. I’m sure once she’s getting better nutrition, things will start to improve. Thank you so much for all the advice!! 
