Were all the birds killed at the neck? I've never had a raccoon kill more than one bird at a time. It could have also been a mink or weasel. I'm sorry for your loss. I lost all but 2 of my call ducks to a mink this fall. He came back the next night for my chickens. I cried too for the loss of my "babies" and because I could have prevented it. It's a terrible feeling, but all you can do is protect the ones you have left and any future birds you acquire.