I agree, she has a respiratory infection, usually the first symptom is a swollen eye, or looking like someone spit in her eye, i also see Mucous coming from her nose ...
I usually treat with Tylan injectable, once a day for 7 days. You can go under the skin at the back of the neck, or into the breast muscle at an angle , not straight in, not deep either , just into the muscle, or you can alternate (AVOID hitting the crop, go on the opposite side !) .. I usually use 1/2 cc for a full sized chicken 7 pounds or so, you would use less for a bantam. ( there are some guidelines on the web)
LS 50 works well in the water for respiratory infections, use one ot the other , not both.. follow package directions, and be sure this is the only water she can get into during the treatment time .. there will be an egg withholding time , maybe 2 weeks after treatment ..
It may have to be drained.. if unsure seek an avian vet , but flushing the eye with warm saline, and warm compress on the area, with the antibiotic , may clear it up...