The symptoms are one, a few, or all. Swollen Eyes, Open mouth breathing, Bubbles in the corners of the eyes, Pale face, Sneezing and coughing and gasping ,Runny nose, Loss of appetite and not drinking water , Not laying eggs regularly as before ,And the surefire last symptom that is a giveaway they have Infectious Coryza is a putrid smell coming from the nasal passages. Once the chicken has this disease and is cured, that chicken never gets it again but they are still a carrier for life to give it to other chickens that have never had it. Don't waste your money on antibiotics that are used in drinking water, or Sulmet. Bytril (enrofloxicin) may be used but is vet controlled and very expensive. The best way to fight this infection on the upper respiratory system is by using Tylan 200. This is an injectable medication. It is found at Tractor Supply or about any feed and grain type stores, for about $32 for a large bottle that will treat many a many chickens. Once the chicken gets the Infectious Coryza give it 3/4 of a CC shot injected directly into the breast of the chicken, and be careful not to use a too long a needle that can get into the internal organs (Use common sense). If symptoms do not improve in four days give another shot. This is what I do and it works best for me, YMMV. Remember this is a treatment for a sick bird and not a vaccine.