Ravens are my absolute worst predator! It started with the full grown Pekin ducks. The ravens would hop along on the ground next to the duck and peck a hole in its back until they killed it. I put some 13 ducklings in a grow pen and came home to nothing but feet and heads left. I let my chicks out to free range while I was working outside. I ran inside to use the bathroom and came out to find that in that short 5 minutes I was in the house, the ravens had taken the heads off two of my Polish chicks. They pulled quail through 1/2" x 1" weld wire. And, last year, they ganged up on one of my kid goats and killed it. My grow pens are, and always have been, covered. My Maremma has finally decided that ravens are a threat and runs them out of the big pen where he stays with the goats. Owl decoys do not scare ravens off (did I mention that I saved a great horned owl from the ravens????). I've used bottle rockets, fire crackers, bb guns, reflective fluttery tape, and .22 to try to scare them away but they just keep coming back. I've heard that a dead raven silhouette is supposed to scare them off but my 3D raven decoy hanging upside down from a tree didn't seem to have an effect. I feel your pain and can totally sympathize. If you come up with a solution, please share it with me.