I have an existing flock of 16 hens, all 2 years old. Three days ago, we adopted 12 more hens and 4 ducks from a family who's owner had died. We don't have much history on these hens, except that they are "a year or two old," and have all been in excellent health, until now. Several days before we adopted them, their family noticed that one Partridge Rock hen was limping. As the days progressed (probably less than a week, from what I'm gathering) she's gotten worse. The day she came to us, I noticed that she was limping and sitting down alot. I left her with her flock for the first evening and the next day because I wanted to observe her and figured the stress of her relocation was better dealt with as a flock than by being isolated. And from what the family was telling me, they thought that she simply "injuried herself somehow." Now that I've had the chance to observe her, she is panting, she sits most of the time with her legs under her, not splayed out to the side. She does look like she's limping significantly, not just dragging a paralyzed leg when she walks. She does get up to drink but I have yet to see her eat. Her poop is watery and mostly clear with some white uric acid crystals. Her comb and wattles are somewhat darker red/bluish/purple than her sisters of the same variety. No nasal or eye discharge or color change. No obvious outward injury to either leg. They move well when I examine her. Her toes clench around my fingers bilaterally when I hold her. I cleaned her vent and hind quarters because they were caked with poo because she sits in it when she expells it. Her breast is lacking some feathers, probably from all the sitting. The area below her vent is also a little feather bare and looks matted. Her skin in the area of the breast where the feathers are missing is BRIGHT red, and I mean bright red! I quarantined her today to a bunny hutch, in the same barn as both my old flock and new flock resides. My flocks are side by side with a wooden wall 3/4 of the way up separating them and chicken wire on the top, so there is shared air and movement of potential viruses or bacteria between the quarantined chicken and the new and old flocks. I'm concerned that 1. I've just infected my healthy existing flock with something. 2. That the flock I've adopted will all succumb, if this is Marek's or some other nasty virus. Tomorrow, I plan on trying the hypericum treatment that I've seen posted here. Beyond that, is the amount of "quarantine" between the flocks and sick hen enough? They are not sharing feeders or waters or outside space at the moment. Should she physically be in another place altogether, because it's an airborne virus? Should I be disinfecting my boots as I move between the two hen houses? This is so frustrating. I was so excited to be getting new hens and these ducks, now I'm worried that my entire flock is at risk. Can you all help?