Thanks all...no, it's no downer, the raccoon was my first thought but with absolutely no signs of a struggle it's hard for me to accept. We didn't even hear a sound, and those girls can be loud when they want to be. My mom thought eagle or owl, something that could have swooped in without a trace, but that also seems unlikely..this was a full grown large cayuga (and a VERY fat one at that). No she couldn't be under the house, it is 2 feet off the ground. We don't have any real bushes or anything for her to be hiding in either. I really thank you all....it's just so frustrating to not know. I mean, if there was sign of predator then I would know it is a security issue but for her to completely disappear? Hubby even suggested someone stole her, which would make the most sense to me of anything but someone who would do that while dh and I are sitting in the room nearby has got a lot of guts. Plus she wasn't anything special, except to me and my daughter. I do wish we had some sort of closure, bury her or something instead of being on edge listening for a quack that will never sound. Ugh, I wish I didn't get so attached. I know they don't last forever and I wanted them for eggs only but this one duck was hard not to love. She was so good, she would hop into my daughter's lap and even snuggled with her beak in the cook of my daughter's neck. We have decided to accept that she is gone and just focus on making sure the other 3 are safe.
Anyway, thanks for letting me vent! Hubby is sick of hearing about it but while I'm telling myself she's gone and there's nothing we can do, I keep thinking she might be lost somewhere-alone, scared and hungry. But I think that's just "wishful" thinking. Hope can not change reality.
I guess all I can do is treat the situation as if it was the raccoon and make sure ducks are locked up early and reinforce the weak point.