I'm totally stumped. I go out today and can't find one of my five ducks (muscovy). They have seemed fine. I find it dead in one of the duck enclosures. Like it went to sleep there and just didn't wake up. It looks normal weight, perfectly fine, but ....stiff. So I'm inspecting the others, and I see one isn't moving as fast as the others. I have a drake and three hens left, this one does seem smaller than the other hens all of a sudden. It seems to be a little wobbly and doesn't have energy. I made sure it was eating and drinking and it swam in the pond, but it isn't standing up on its legs and it kind of creeping around the duck pen in little bursts of effort, like using its legs is just a huge chore and sometimes rests its beak on the ground. Yet I saw it paddling its legs normally in the pond. This one sits looking dully at the ground unless I disturb it, when it makes an effort to escape me. My other three are walking about normally. Any ideas of what is wrong with my birds? I'm really bummed about the one that died and this one that is acting weak is my 14-year-old son's favorite, her name is Daisy. He is going to be heartbroken when he gets home from school. I suspect we might bring her into a dog crate overnight and make sure she gets plenty of food and water and ......do any of you have any ideas? I did have another duck die a few weeks ago. I thought it had not figured out how to get into the new duck house and didn't get any food. These ducks are virtual twins so we can't tell them apart except the Don the drake unless we inspect closely so we could easily have not realized that a certain one didn't go in. I was hoping for some clue as to what happened and what I could do to help Daisy and prevent further loss.