Need help! Newbie! Foaming at eye and mouth.
Welcome to BYC. Sorry about your poor hen. Place her in a crate or cage inside for a few days to watch her. Clean her eye with some cotton and water. Put some Vetericyn Eye Gel or Terramycin Eye Ointment (from a feed store) in the eyes twice a day. Watch to make sure that she can see her food and water. Look for any diarrhea, or other things out of the ordinary, such as nasal drainage or noisy breathing. Sometimes other chickens will attack a weak or injured chicken. Is she starting her molt? Is she laying eggs? Has she been wormed recently?
You can purchase some Vetericyn Eye Wash or the Eye Gel from a feed or pet store, and clean the foam or debris out of the out eye before each use. It is non-antibiotic. If the foam is caused by mycoplasma, though, you will need to treat it with oxytetracycline or Tylan. Mycoplasma (MG) is a respiratory disease that causes symptoms such as foamy eye, swelling around an eye or the face from sinus infection, nasal drainage, cough or sneeze, and noisy rattly breathing. Any or all of those symptoms may be noted. Here is some info about MG: