Call a game warden and NOT the local police or troopers as they have no idea about laws governing the killing of livestock. 20 years ago I lost my entire flock (40+ birds) when a stray lab and Doberman decided it would be fun. (I was finding dead chickens by the smell for the next 2 weeks. The...
Most states have laws permitting the owner to protect the flock and that includes a lethal response. Call fish and Game and tell them to stop the attacks anyway they can. Do not threat or tell them, but be prepared to handle it yourself.. My area is loaded with bobcats, fishers coyotes, coons...