ok first no need to cull you can pull out all the stops and try to treat if you want to
first lets figure out the problem.
can you take pics of the eye?
list all symptoms and look for mites and anything else that might be effecting her.
was the eye injured? or is is a growth?
First thing is first she needs to eat.
will she be hand fed or does she need to be tube fed? if the later I will walk you through it.
also get the following ready
Shredded apples, organic or real live cultor yogurt, rolled oats, hard boiled egg yolks, poly-vi-sol, vitamin E, and butter milk.
you will make a mash of that food (add a few bits of grit and sprinkle with scratch if she does not want to eat it)
ETA if she is acting fine, just research eye problems and treat accordingly, she can live fine if only blind in one eye although her depth perception will be off. Chickens adapt very well.
if she needs to be tube fed then you will make it in a blender or mixer so that it is a little thicker than water you can thin it with water to get it that way and omitt the oats in this case. (you want it a warm temp not cold)
then you should clean out the eye, get pics and post them.
