hen wont eat or drink has watery eyes.. please help dont want to lose my hen or expose the rest of m

[candiceg143]

I am new at owning chickens and have recently purchased 6 together. One week ago this past Wednesday I brought them home and all of the chickens have been fine since until yesterday when one of my barred rocks stopped eating or drinking and developed watery thick discharge in eyes. I have gotten antibiotics from tractor supply but they are to be mixed with water and she wont drink :-( I currently have her quarantined in a dog crate in my house with medicated feed and water.. she also has a streaked up vent but her stool appears normal (white and green/brown) not overly runney. Is there anything I can do?! I hate to lose my entire flock or even her :-( feeling so helpless right now...
Candice