You could try giving her medicated fluids often with a syringe down into her crop or tube feeding. Here are some links about giving small amounts of fluids down into the crop:
https://unitedpeafowlassociation.org/articles/oral-medication-dosing-of-peafowl/
Tube feeding:
https://unitedpeafowlassociation.org/articles/oral-medication-dosing-of-peafowl/
Tube feeding:
