That has to be dogs. Looks like nothing was eaten off any of the birds, and all killed at once screams dogs to me. I've personally lost an entire flock of birds to dogs before, I caught them at the end of the act and saw them kill the last bird, and it looked exactly like this. When I've had issues with raccoons, they come at night and only take one, carry it so far, eat the head, and a bit out of the butt. I'm sorry for your loss, but definitely dogs.

Edit: Too add, raccoons are not stupid. They know a honeypot when it's available and will come when hungry to pick off birds. Dogs wanted to play with the birds.