If she is not being picked on by others, I would put her back with her flock. She could be placed inside a dog crate with food and water inside the coop or run, if you need to separate her for a day or so. When they are passing lash egg material, antibiotics may be too late. If you decide to use an antibiotic, amoxicillin or enrofloxacin (Baytril) are common ones used for reproductive infections. Both of those require a 2 week egg withdrawal, and I might do a longer one for the latter. The antibiotics are very hard to get without a vet, but enrofloxacin is a little easier until it is no longer available. I would let her decide what she wants to do, and spend time with her flock.
