Pekin duck advice

[PeachstateDuck14]

I have a pekin who is having a hard time walking and looks like this underneath can anyone help asap

 

[PeachstateDuck14]

 

[nuthatched]

What are you feed? Any niacin supplements?
.edit: holy moly, I don't think she's supposed to look like that.ruthh
@Miss Lydia
@ruthhope

 

[PeachstateDuck14]

I’m aware. She has dry food and greens and water.
Someone is telling me water belly

 

[Canadian Wind]

Looks like water belly to me. Sorry, I'm unsure of the treatment.