Chickens with infectious bronchitis virus do not remain carriers past a year. Some articles say 5 months up to a year after recovery. So new chickens who are not exposed, should not be affected. I had IBV affect most of my flock in the first couple of years. Many of the hens had reproductive...
I would stop at that. Too many antibiotics may really mess up her beneficial gut bacteria. Probiotics for a week or so might be helpful. Salpingitis is not a curable disease, but hopefully, the antibiotics will help to prolong her life. The best thing for her would be that she would stop laying...
Give a human calcium citrate tablet with vitamin D to help muscle contraction, and keep the prolapse tissue moist with honey or ointment until it goes back inside.