poorly hen

My 21/2 year old hybrid started to look down in the dumps 5 days ago - at first she  just had a floppy comb and was acting normally - but she detiorated over the weekend, she has now stopped eating and is very lethargic.  She is also regurgitating foul smelling liquid ( vet said not sour crop as crop is empty). She has got diarrhoea but it is not green or yellow or very odd. I have taken her to my vet who is not a chicken specialist and he does not know what is wrong with her.  She does not have a temperature and her breathing sounds fine.  He has given me Baytril but I felt sure some of you out there would know more than my vet!   I have just looked at her again and she is standing now.  All advice most welcome as I have other chickens and bantams and wouldn't want them to catch anything.

still going is very weak and still seems to be bringing up this foul smelling liquid

have just been out to give her antibiotics - she can hardly stand - I held her upside down and lots of this foul liquid came out - her crop is empty as she is not eating - so should I continue with the antibiotics or is there an antifungal treatment she can have?  Not sure she will make it through the night.

vet prescribed the antibiotics but didn't know what was wrong - she bought up some liquid while at the vets and I did suggest sour crop - but vet said it wasn't as her crop was empty - but there was a considerable amount of liquid this evening even though she hasn't been eating.,