Abriana, I'm sorry to hear about Christine@Wyorp Rock I went out to give my littler babies some fresh water and I found Christina dead under the coop. I am quite miffed in fact, her comb was a purpley color, she was on her stomach with her wings slightly splayed. I found one of my ducks out (they have a separate pen next to the chickens divided with electro netting) and I am very worried that maybe he tried to mate with her and that killed her? None of the other birds were hurt. I am extremely upset, Christina was very very special to me, and I am angry at the ducks. If they did do that I don’t know what to do, it’s hard to keep them separate because they can fit through the fencing. The medicine was coming today and I was so excited because I thought she was going to get better. I’ll have to talk to my dad about a separate solution for the ducks, I thought this would work but I don’t trust them. I don’t really even know if I want to keep them anymore.

It would be really hard to know what happened unless you had a necropsy performed. It's very possible she suddenly succumbed to whatever condition that was causing her decline.
Trying not to get too graphic here but, once a bird dies, the comb will often turn purple. There's also some residual movement/flapping and this can provide enough momentum to send the bird into some awkward positions. So even the place or position you find them in may not be where they died.
You know your flock, your ducks and your situation better than anyone. You must have seen something for you to have concerns about the ducks, but unless you actually see it happen, it would be speculation that one of the ducks harmed her. I've had hens seem to get better for a short period of time, then suddenly they were gone, so it's very possible she just passed quickly and from no interference from the ducks.