I have been treating my two-year old Golden Sex-link Pearl for a year for a reproductive infection. She's losing weight, has diarrhea tinged with yellow, and while she takes part in daily flock activity, she hasn't been her high octane mischievous self in a year. I began treating her with Doxycycline, and when that failed to improve her, I went to amoxicillin, and when that didn't work, I went to Clindamycin, and that didn't do anything, so now she's on Triple C, another "cycline".
Four antibiotics and no change. That should tell you how stubborn reproductive infections are, and I began treating her very early, too.
No, I do not plan to cull her. As long as she's having a life, eating, mingling, enjoying free ranging, she will remain in the flock, but I will euthanize when her quality of life suffers.