Someone I know here in the UP had nearly their entire flock slaughtered by what is likely a dog as they free ranged. The kill pattern is that classic play with the squeaky flappy thing until it is dead, then catch the next one. None of the birds were eaten. One duck survied, but is injured. The vet even agrees from the spacing of the teeth marks on the surviving bird that a dog is the culprit. I hope she can catch the dog, if it comes back for more 'fun', then send the owner the bill for getting all those hens to point of lay. They were pets as well as egg layers.