Now that it's light, everyone is home and we can actually see, we are 99% sure it was a dog. Pile of feathers in 3 spots, 2 blood spots and then where she died. This was someone playing with the chicken, not someone grabbing an easy meal.
She is a herding dog but she does not "herd" she jumps and grabs at my dog. She grabbed at the chicken multiple times and got nothing but feathers (Cochin.... so 98% feathers, 2% chicken) so she went for the head.
Chickens are locked up in their 100x100 run today (they're just a bit spoiled) so I can keep an eye on them and I left the dead body right in front of the run where she died... I have a scoped .22 sitting on the kitchen table. If it's a coyote it's going to be shot, if it's the dog, I am going to go dump her off at the nearest heeler rescue.
She's unlicensed, no tags, no microchip, no nothing... not even a collar. Oh and she is of course intact.
She pinned my 103lb BullMastiff down yesterday morning and ripped the bandages off the 21 staples in his leg (had cancer surgery) when I let him out in MY YARD to go potty.
I am done, done, done. I won't shoot the dog as it would be a perfectly wonderful dog if given some training, exercise and SOMETHING to do. Not thrown in a small fenced area and left to rot until it's old enough to "make babies". It's a purebred blue heeler, I'm sure a rescue could find it a suitable (non-chicken now that's she's tasted blood) home.