I have a 7 month old Black Star that started acting very lathargic about a week ago. She walks around slowly like she's drugged or something. Sometimes she roosts in the coop at night and sometimes she stays in the run. She makes her way to the feeder and waterer alright but has stopped laying. To be honest, I expected her to have died by now. The rest of the flock is just fine. She eats healthy and I've given the flock ACV with every watering throughout thier lives. Can anyone give me an idea what may be wrong with this poor chook?