White poop residue on her feathers is a classic sign of Avian TB. I'm sure it's a sign of other things, too...but we had three hens that had it and they all had that symptom. Other symptoms can be pale comb, progressive weakness over a period of months, rattly breathing, increased lethargy, no more egg laying, and lameness...but is a very slow progressing disease and the chicken eats and acts pretty much normal til the last;...in all three of our cases it took nine months from the start of symptoms, til when the hen died. One of the last symptoms they had was the white poop stuck to their feathers, although not all of them exhibited the other symptoms I mentioned, they all had that symptom. If that's what it is, there is nothing you can do to cure it, but you can help them by making sure they are parasite-free, and have a good healthy diet. Fortunately, it is not necessarily contagious to the rest of the flock. (and I speak from experience, thank God!) It is a kind of chicken cancer that they pick up naturally, and, either they get it, or they have an immunity to it. I hope I don't sound like the bearer of doom...and I have to stress that MAYBE that's not what it is....it might be nothing much. It's just that that 36 week (nine month) thing, and the lethargy and the white poop, rang a bell. There are so many look alike things though. Watching and keeping em as healthy as possible are probably the best thing you can do, I think. We understand what it's like to wait for advice and not know what to do in the meantime. Good luck to you and your hen.
