Poultry Talk Ontario (pto.ca)

One of my old girls is not feeling her best tonight although it took my a while to notice. She has bubbles in one eye, a bit of a head shake and sneeze. This is a first for me and I've been bracing myself for it. I'm having a hard time keeping humidity down in my coop the past month or so and was afraid something like this may crop up. I've brought her in and inspected everyone else-so far they seem fine. Will clean my waterers out tonight and disinfect.
This girl seems very spry and is eating well. She's pretty mad to be in the house right now and I'm hearing about it! I'm trying vetrx tonight and will see what morning brings. I may be over-reacting but if I did nothing and she went down hill this evening I'd never forgive myself. She's one of my originals and will be 7 in spring. She's also the only one who's never been sick.

@Happy , IMHO, you are not overreacting.
It sounds like mycoplasmosis to me. My very first hen had that, but I did not get her on the right antibiotics early enough. I started with antibiotics that I could buy from feed stores at the time. When there was no improvement, I asked for advice and a veteran forum member recommended that I find a vet ASAP that would prescribe either Tylan 50 or Baytril. Baytril apparently is the better of the two, but both will do the job.
Good luck!

Thanks @Jaye
I don't know if she's playing me or not. Before I even had a chance to go at her with the vetrx she stopped sneezing, her eye dried up and she stomped around the house screaming her indignance. She's eaten an egg and part of hubby's burrito. She will have a comfy sleep on a pillow and old blankets in the dog crate tonight and reassess in the morning.

Sounds like the difference is she’s not in her coop anymore . Sounds like poor ventilation in your coop . Somewhere in these pages probably coop designs or health there is info to help you .

FYI ....purple lines are air movement stale moist air out . Fresh in

Thanks @ross
I'm hoping that's all it is. I've never had an issue in 7 winters but I have more birds in there than I've ever had so I think I need to get some more ventilation added asap. I have 2 gable vents at the roof peak, soffit vents and adjustable vent holes about a foot off floor.

How big are screens . Usually soffit vent screens are to small & fill up with dust . If so cut/take um out & replace with 1/4” or 1/2” woven wire .

Thanks again Ross. Will look at those vents tomorrow. For today the windows are open and my old girl is back outside and still symptom free.

No, you're not overreacting! Better to separate and find out you didn't need to, than not separate and then wish you had! If she's shaking her head, whatever it is is bad enough that it's irritating her airway, and it could be anything from grain dust to mold sensitivity to MG to serious illness.