We have have lost 2 ducks in about a week and do not know what is happening. The first duck we lost was a male Pekin about 4 months old. We thought he had limberneck. We detoxified him by using charcoal and epsom salts and gave him antibiotics for about a week. He was showing improvement, and then took a sudden turn for the worse. He could not uses his legs and was trying to get around by pushing his wings on the ground. It was so sad, we had to put him down. One foot and leg felt hot and he seemed feverish and was shaking. I could not find any injury to the foot or leg. This morning one duck was off by its self which is very unusual. They mostly all stay together (3 khakis and 2 pekins). A few minutes later when I fed them the missing duck showed up but stayed in the pond while the others came to eat (this is also unusual). Last week we drained the duck pond and refilled adding a few chlorine pellets to try to kill and bacteria that may be present. I feed the ducks chicken layer feed. I appreciate any advice, help or ideas anyone may have.