Feed her only duck feed, no treats until this is resolved.
I agree. Cut back the treats other then 1ml of durvet vitamin B complex ( best to deal with once niacin issues are server )
Can get at TS or on
Amazon
Over a few peas like 4-5 type thing or by syringe orally
Mix up 1cup feed and add nutrition yeast 1tbs together then feed her from the mixed
The swimming is great to help take weight off and use the leg
Keep doing that as well
Changing these few things maybe the key
Can also put Nutridrench in her water for the extra all around vitamins she may need
Check the bottoms of her feet to make sure there are no sores or bumble foot starting too
I know this can be a long process and day after day seems like there is no change but all of a sudden they can get better
Just had a duck who had a fungal issue in December
Vets missed it and dealt with the bacterial and that made the fungal worse.
We have now been on fungal meds tomorrow will be 60 days and I only started ti see improvements at day 50
50 days of meds and no change then all of a sudden things were getting better