Does her eye look as though an animal (other chicken, predator, etc.) destroyed it, or is it just swollen shut/scabby? Her lack of interest in feed and water could be because she has been injured, either externally and/or internally by an attack. I'd keep her in a warm, clean place away from any other chickens. Continue getting her to eat and drink; perhaps put some vitamins/electrolytes in her water to boost her strength. Given some rest, she may recover, though she'll be missing an eye.
Of course, she may have been beat up because she is ill with something, in which case you need to treat the underlying problem. I would consider getting some 9.6% Corid liquid or 20% Corid powder from a livestock supply store and treating for Coccidiosis. The dosage is 2 teaspoons/gal for the liquid, and 3/4 teaspoon/gal for the powder, given for 5-7 days (do not give vitamins during treatment). It's also possible that she has some sort of respiratory disease, but before treating for that (you would use an antibiotic like Tylan50), I would give her a chance to rest and recover.
Lastly, does she have any other symptoms? Is her crop large and squishy, or hard packed? Can she move her legs and wings properly? Any discharge from the nostrils, or bad smell coming from her mouth?
