I wouldn’t cull her especially if she has been a part of your flock. MG is pretty much everywhere, kind of like Mareks disease. MG is a common bacteria found in a lot of the reproductive disorders, such as salpingitis and internal laying.
As
@dawg53 said, it might be something in the eye or an injury that has caused the bubbles. There was someone the other day on here whose chicken had been attacked and pecked, and the chicken had eye bubbles in one eye.
I would get some Terramycin eye ointment and treat it. If it doesn’t improve, then I would use Tylan 50 injectable, but give it orally. It is a cattle medicine at most feed stores. You could do both now if you wish. Dosage is 1/4 ml per pound given orally 3 times a day.