Start an antibiotic.
@Miss Lydia do you still have the link for where to get Baytril?
Also start giving her niacin.
This is the best if you can get it it’s for sale at most Feed stores and on
Amazon as well -
Give one ML per day , orally, following these instructions
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/
Bring her in to float for a few hours in your bathtub every day if you can. Just lukewarm water.
Also, if you get a 5 gallon bucket with a lid and cut a hole in it for her head to pop out, you put her in there with about 10 inches of lukewarm water in the bottom that that has Epsom salt salts mixed in. And let her soak in that for half an hour once or twice a day.
You can also start giving her something for pain and swelling like meloxicam.
There are a couple others that are safe for Ducks,
I’ll try to get back online later with some more suggestions and dosages.
When she is walking around free in the yard, you can wrap her foot and leg with Vet wrap. There are several good videos on YouTube showing how to wrap a Ducks foot. You have to be careful not to smoosh in the webbing . and you should leave the nails out from the wrap, especially the dewclaw in the back.
There is also Epson salt poultice that they make for horses, you can use that on the swollen areas before you wrap it . Poultice, gauze , vet wrap.
Another thing you can do is make a sling for her. You can even use a rectangular shaped laundry basket and a towel with holes cut in it for her legs and attach food and water bowls in front of her so she can just kind of rest in it and her legs hang down. There are also links showing how to make nice slings for ducks and chickens. If you can’t find them I will try to post one later as well.