How much Tylan should I give ?Injectable

Are those bubbles in her eye?

Any respiratory symptoms? How does the bird act otherwise?

 

IMO the symptoms sound a lot like possible mycoplasma. https://poultrykeeper.com/respiratory-problems/mycoplasma/

Now I am sure someone will pop up and say kill every bird on your property, burn the coop down, salt the land etc... But don't over-react. Are most of the other birds healthy? Any new additions?

I had an EE pullet with those symptoms, later found out the breeder I bought her from had Mycoplasma in her flock. None of my other birds have ever showed even a hint of it.

 

What about Coryza, sinus infection?
I would separate her from the rest of the flock and gently wipe her eye with a warm wet cloth or something and try to see if you can see anything in or on the eye that might rule in or rule out anything.
I don't know much about this but am doing some research.

 

So they are temporarily staying at your house? That would be stressful, and stress can trigger an active MG episode.