Please provide some more information so we can help you-
You went to the vet and got antibiotics.
- what was the diagnosis?
- what was the antibiotic prescribed?
- how long was the antibiotic supposed to be given/ how long has she been on it?
How old is she?
What kind of duck is she?
What are you feeding as her main food?
Does she have free access to grit and oyster shell?
How frequently do you offer treats (besides the worms)/ what, if any?
....did the vet do a fecal float?
How is her poop?
How does her crop feel?
Any funny smells from her mouth?
She isn’t eating well, but.
Is she drinking/ bathing? Preening/ grooming herself?
Is she with other ducks?
If so, how is everyone else doing?
If you can help with these questions, I would hope that
@Miss Lydia @New duck mommy 2021 , myself, or someone that they tag in might be able to offer some thoughts...