This is a crime scene of my. You see, like some heavy fight was going on. What could do that? Bird predator, wild predator or neigbors hungry dog?
Sorry to hear it came to that. Dogs are less to blame than their owners but they only let you punish the dogs. Sad part is 9 times out of 10 you suddenly become the bad guy.
Once again, I'd mention that an electric fence is a good solution to problems like this. You start with a totally safe, predator proof coop at ground zero....a coop nothing can get in or out.....day or night..... and then establish a safe zone perimeter around that with an electric fence. The fence deals with the bad guys so you don't have to.
The certainly looks like the work of a hawk or some such bird of prey. They catch the bird, then pluck out breast feathers with their beaks, spit those out and start eating. A big patch of dry feathers scattered like that is how they leave it. As for the remains of the duck, hawk ate what he could hold and left.
The 2nd duck with missing tail feathers may have been the dog. Dog got close, but duck got away?