Bump behind eye?

[OneLostHen]

Well Greycie passed away last night. She developed a gargle sound all day yesterday with some gasping motions. Stopped putting herself in the coop at night (I picked her up and placed her inside) and lost balance worse.
But she ate till the very end.

 

[Susan Skylark]

I’d guess some sort of chronic sinus infection that spread to the inner ear, maybe a mycoplasma? Very hard to treat even with oral antibiotics, topical won’t touch it or home remedies. Mites are separate issue but immunocompromised birds are more prone to secondary issues. The bump might be caused by internal pressure (gas or fluid) or might be totally unrelated. Sorry for your loss. The good news (if there is any!) is that certain types of mycoplasma (like synovae) are spread vertically (via the egg) and not horizontally so she hopefully didn’t pass it along.

 

[OneLostHen]

That is the most plausible explanation I've read. It gives me some relief.
Thank you! She will be missed.