I agree with Coach723. He is most likely blind, but they can see light and dark usually, according to what I have read. The ointment will help to prevent infection.
I would start a new thread where more people will answer. It almost looks like the eyeball was punctured. Can you handle him well enough to use a warm wet compress and hold it on his eye for a few minutes to soften the goop? You can then flush the eye with saline eye wash, and apply either...
Here is a site that sells the MG vaccine for chicks at least 1 week old:
https://www.jefferspet.com/mg-bac-1-000-d/p?idsku=6344&gad_source=1&gclid=CjwKCAiAi6uvBhADEiwAWiyRdnR_VxG_E_Ch6dtlN1NR0bHcBQTHucE2fBqV7BRMKrbRK2VrAmrTiBoC86gQAvD_BwE
There are a lot of articles about MG online to read...
Mycoplasma gallisepticum (MG) is not a virus, but an organism similar to bacteria. Antibiotics may help treat it, but they don’t treat viruses. There are a few viruses that cause respiratory disease symptoms, but those are infectious bronchitis and ILT, and others. Her symptoms sound like MG...
Yes, MG contagious. Not all birds will have symptoms. Your flock has already been exposed. They will be MG positive, but you could try to get this one hen tested to confirm it. Are you hatching new chicks, buying them from someone or a hatchery, or do you already have them, and are just waiting...
Those symptoms in her eye is conjunctivitis. They can have a sunken appearance with the pink showing. If it were me, I would give the Tylosin, but that is up to you. It is very safe.
Here are some links to read:
https://poultrydvm.com/drugs/tylosin
Scroll down to the last 2 paragraphs for Tylosin presence in egg:
https://www.sciencedirect.com/science/article/pii/S0362028X23062567
I don’t know anyone who uses an egg withdrawal for Tylosin. In the past when using injectable Tylan, even then the egg withdrawal time was only 1 day. You can be extra cautious if you wish.
I would treat with Tylosin powder in the water in addition to the eye care and ointment that Coach723 recommended. She may have mycoplasma gallisepticum (MG?) She doesn’t need to be isolated unless others are picking on her because she is ill. The marks on her comb are probably from pecking...