An infection from a peck wound or foreign object might be a possibility. Examine inside the eye for any seeds, dirt, or look for peck wounds around the eye. Squeezing the pus out or cleaning it out with QTips, then applying an antibiotic ointment such as feed store Terramycin can help. Tylan will treat respiratory bacteria, but if it is E.coli or another common bacteria from the bedding, it may require an antibiotic specifically for gram negative bacteria, which would need to be prescribed by a vet.