All evidence reported reads like an owl. To differentiate between owl and raccoon, look at feathers still attached to body and close to where predator actually fed. The owl will leave feathers in that area clean and dry. The raccoon will leave feathers in the same are with a wet slobbery look. Raccoon will bite through a lot of bones leaving what look like shards while the owl will pick bones clean of tissue and some times eat the bones whole. Owl, like a hawk, will cleanly pick muscle away from neck vertebrate while raccoon will often chew right through bone.
Raccoon will not hesitate to make multiple kills if victims close together. Owl usually will kill only one.
Surprisingly, you can hear both critters when they are eating a carcass from some distance. Great-horned owl will snap tendons and ligaments as it feeds. Exception for owl breaking bones involves those that are flat like in the breast and back supporting flight muscles of the chicken.
The only thing that throws me off on an owl is, if I am picturing this right, some birds are in the coop and those appear to have been safe, while those under the coop are either killed and dragged out or dragged out then killed. In this case the predator would (in my mind) be going under the coop. I always think of an owl swooping down, not walking under something unless the coop is high enough off the ground for him to swoop under. The cam should be interesting and hope it gives an answer.