Okay, so early this spring I bought a dozen Ancona duck eggs and ten hatched. They were overall a healthy, cheerful bunch, but a few months into their lives I found one of the males laying on its side one morning, dead. No marks, no symptoms. In September, eight little second-generation Anconas hatched. One broke its leg and stayed in the house with a splint until the bone healed. But then, about a month ago, I found one of the ducklings dead on its side. Its legs were out behind it, but its neck was in a natural position. A week later, a second duckling died, too. Again, no symptoms of anything. Just a dead duck. I'd like to point out that my ducklings free-range during the day and are shut up at night with food and water. The adult ducks got shut up in a different pen at night until a week ago. Two days ago, I let the quacks out of the pen and saw that a few of the adults were limping a bit. Nothing serious, I thought. Until that night, when I had to find both a duck and a duckling with a flashlight. The duck had runny nostrils and a cough. The duckling mostly looked sleepy. Both birds had slightly fluffed head feathers and looked sort of like they'd been crying. Anyway, my parents and I looked up diseases on the Internet and picked the most promising option out of our livestock medicine cabinet: Tylan 50. So Dad and I went outside and gave an oral adult dose of 1mil and a duckling dose of 1/2mil to the Anconas and their roommates the Black Swedishes. It's funny how "limping" doesn't mean "slow." I made sure they had clean water and food and tried to think happy thoughts. The next morning everyone was still alive. One of the drakes that had been limping seemed completely better. The duck that I'd had to hunt down was neither better nor worse. Two ducklings were now limping. In the evening, the first duckling was laying on its side, dead. Dad and I gave all the non-healthy ducks another dose of Tylan 50. This morning, a few more ducks were limping. The one that was badly off seemed to be improving, as did the second limping duckling. I gave some medicine to a new sick female (adult) and felt a bit optimistic. Naturally, the duckling was died between visits. Extra info: 1) The Anconas stopped laying nearly a month ago. They do have a light at night. 2) The poop of the sick birds is green. 3) Two two-week-old Muscovy ducklings died this afternoon. It's possible I tracked the germs, but they're in a brooder and shouldn't have been exposed. 4) None of my Muscovies have gotten sick. Or the Black Swedishes. (I love the irony behind this—expensive, rare breed? Best-colored ones dying? Check. Check.) 5) The two ducklings that died were only half-feathered. Their siblings have everything except wings. 6) Some of our chickens caught "the cold" in the spring and were given an antibiotic, but ducks drink too much for that particular medicine. So, please help? I'm sorry the post was so long, and if anyone has questions, I'm definitely willing to answer.