Has she been eating ok? While she's been seperated can she still see your other ducks?
In our experience when we've had to seperate any of the ducks they seem to eat better and be much happier if they can still see all of their friends.
That's fantastic, Very glad she is looking better after some TLC :)
Our girl actually passed away due to totally unrelated medical issues, which was how we noticed her skin issue in the first place.
All the other ducks are looking good, happy and healthy so her skin issue didn't seem to be...