I've got some chicks that were hatched out by a broody hen about 3-4 weeks ago. I noticed one that had one eye shut. Still eating, still drinking, acted fine. A couple of days later I noticed that another one had one eye shut, and was having trouble breathing. Then the original one that had the eye shut, it was oozing. I immediately gave them some duramycin. Those 2 didn't end up making it. I now have 3 others that their eyes are getting gunky. I am still giving them duramycin but I have no clue what this could possibly be! They are all still eating and drinking fine.