you aid you be seen her eat? Is she actually making contact with the food and swallowing? I've had then attempt to eat and fail before.
I had one do something similar and I tube fed her and (as much as I tell everyone not to do this) threw amoxicillin at it. After 4 or 5 days of tube feeding and amoxicillin she started eating and drinking. Went through a 10 day course of meds and she is now fine. She is not laying again yet though, but is healthy otherwise.
When I found her she was just standing in the nest box leaning against the wall like she was drunk.
She ate some goodies. I had some bread and bananas I brought out for everyone. That's what I saw her eat. I may have to bring her in and monitor a meal. I have penicillin and some cipro. I hate to throw meds at unknown illness too. I had given cipro to the older girl and she seemed to get better. Then again that didn't end well. I can tube feed if necessary.