AFAIC, once a dog kills birds, it knows they are there and will be back.
I have no special love for dogs and will kill them just as easily as any other animal that fits on a plate.
Food for thought if you want to protect your flock. If it's a stray then it absolutely needs to go, if it belongs to someone, they need their (_*_) beat unless the dog just that one time escaped somehow. File a police report if you need to. Some people own animals who have no business owning animals.
I had a friend who lost a whole flock of guineah's to a neighbor's dog, the neighbor laughed and said, I guess I don't have to feed him tonight then. See what the situation is and get authorities involved if need be.
Aaron