Years ago, I had a barred rock with swelling right by her eye, looked similar to what your hen had. The bump was closer to the eye duct, and was causing her eye to be clouded with 'spittle'. I tried a number of antibiotics, but we eventually culled because she became listless and obviously in pain.
I used Sulmet on my flock after I noticed others acting this way, and they turned around. When I introduced more hens to this flock, they also showed symptoms. I treated everyone with Corid this time, and they all turned around and recovered. This is what made me sure that my original Barred Rock was afflicted with cocci, and spread it into my soil.
Respiratory issues are usually secondary symptoms, or they usually pop up in chickens that have a weakened immune system from another culprit. If you're sure there's no worms, then cocci is worth exploring. ACV is good in the water for respiratory support, but I'd advise against treating the water with anything while using antibiotics/dewormers. Let them have a choice, at least between fresh water and treated.
I'm having a very similar issue with a Bantam in a new flock in a different location- head tucked, tail down, isolating herself. I'm not smelling or seeing anything strange in her droppings, but I lost another Barred Rock three weeks ago halfway through a deworming treatment. I'm going to try an antibiotic on the Bantam today.