Her vent area is red and swollen too.
Need your help.
I don't see your photo. It sounds like she is very sick if not eating. I would try to give her fluids if possible, but the outcome may not be good if she has internal laying or egg yolk peritonitis. Baytril is a good antibiotic that is banned in chickens in the US, but still used for EYP, as long as the chicken won't be eaten. If she seems to be suffering, you may want to consider putting her out of her misery.