I am afraid that we have a cycle of illness in our flock. Almost two months ago, some "crud" worked its way through our flock - after we adopted a couple Silkies. They were not sick, but several of my birds came down with a runny nose, puffy eyes. We used Sulmet - to some effect. Later, Tylan injections with a couple of birds that looked like they might not make it. All recovered! We thought we had worked through it all. I now have a Silkie that is very low energy (one of the adopted ones). She will come out into the run with the others, but just sits on a low perch. Earlier in the week, I figured she was trying to deal with the first few days of cold weather. We babied her, fed her special meals with egg and veggies. She has no "symptoms" other than lethargy: poop looks fine, eyes look fine, vent okay, etc. Yesterday it warmed up, my entire flock was really active, except the Silkie. We have quarantined her. She did not eat this morning. DD is afraid she will die. If she does, I will ask for a necropsy and I suppose my question will be answered. I would like to try to save her! Any suggestions????? Thank you!