I have lost 4 hens and don't know why. We are new at raising chickens, so we really need some help here. I had 4 hens and two rooster, then went to an individual to purchase so grown laying hens and young pullets. The young pullets have watery bubbles in their eyes, and snotty beaks. What in the world is it? I have killed all the sick chickens, and plan to separate the last two remaining pullets from my grown chickens. Grown chickens seem fine......do not look sickly. Today I cleaned out the chicken coop, racked up all hay, grass, scraps and burned them. What else do I need to do? Appreciate your help in this matter.