I think centra pretty much nailed it. This rooster was the pack leader everywhere he went all the other chickens went. My dog is old and she had seemed to be helping me herd them up when I put the chickens up. I guess her predator or pack leader instincts took over and it is possible this rooster confronted her, he was'nt afraid of anything. My wife and daughter were checking the temporary coop / run to make sure all the the birds went in when she found my dog chewing on the rooster. She had chased him into the edge of the neighbors yard. I was actually more worried about the neighbors dog getting them then her. I guess I was wrong about that too.
Anyway since I put the shock collar back on her and gave her some DC therapy she has not gone near a chicken. Only time will tell, I know in the past the shock collar has broken every bad behaivior that both my shepherds displayed. The tri tronics has six levels of shock and two different sets of interchangable probes it will work up to 1/2 a mile away. I bought it to train my lab for duck hunting. He was doing very well retrieving until someone shot him. He liked to hang out with my neighbors dog and they would cross the creek below my house and run ducks, deer, or whatever. Someone on the other side of the creek shot them they killed my dog and broke the jaw of my neighbors dog. The vet told him it was a high power small caliber round like a .223 or .243 .
There is a hunting club that has all the land leased on the other side of the creek about a mile down to the Altamaha River. When it is not deer season there is somebody over there shooting regularly and you can tell it is a high power rifle. When I built a small range on the side of my property and started shooting back in there direction they stopped. I guess they figured out that there was neighbors closer than they thought.