We have 18 Pekin duck. 11 are just past the teenage stage, hatched in the barn by their mother so they have always been outdoors. A few days ago we lost one (had 12). His eyes started to darken around them and he stopped eating and drinking and started having seizures. We tried giving brewers yeast, separating him and giving him food and water that he refused. After two days he died. Now we are having some of the same symptoms with another duck. He will eat and is a lot more lively but he goes into the barn a lot and has started having seizures and has the same darkening around his eyes. Any ideas on whats going on? All the other ducks seem fine.