Dropping wing, not as energetic as normal and weak in ducks, any reasons?

[MrDuckLover23]

For the past month or so now, my Muscovy hen has been experiencing drooping wings, not as happy/energetic as normal and is slightly lethargic.

I have noticed her slightly getting better, what I have also noticed is she has a very pale face not a healthy Muscovy red.
She has other ducks so she is not lonely and lives in a clean and healthy environment.

Not sure what the problem is, any answers would be great.

 

[sourland]

is she molting?

 

[MrDuckLover23]

is she molting?

None of my other ducks are currently molting, I think it is a sickness instead. Any other thoughts?