Well, my girl seems to be a bit better, but not much. I decided to put her back in with her buddies when I realized there were two others (maybe 3) with her same symptoms. I still am wondering if it has anything to do with a heavy molt, as the affected ones are in an extremely heavy molt, OR, could it be that due to the molt, their immune systems have become compromised and they cannot fight off whatever this weird thing is?
They are all eating well and drinking well, and otherwise acting completely normally. Poop is normal. A few sneezes now & then, but I'm not overly concerned about that.
I've decided to do a radical quarantine: I'm converting one of my barn stalls into a temporary chicken pen. I'll move them over tomorrow, thoroughly clean their coop & disinfect it, rake the ground of all debris and remove all their chicken toys, and then thickly spray the ground, coop, walls, and fencing with Oxine solution. I will leave it for 3 weeks, and then return them. Poor girls will not see the light of day (except through the plexiglas panel in my barn roof) for 3 weeks. But, I feel like I need to start back to square 1, which is disinfecting everything and letting it sit for the recommended 3 weeks.
I'll report back when the quarantine is overwith. Crossed fingers this works!