It's too late to call the sheriff once your bird is dead. I mean I get the point of reporting it the first time. But I am talking about a second time. That dog will be back and I suggest you arm yourself or you'll be burying more of your flock.I had my neighbors dogs kill my rooster yesterday. He was so injured he crawled up onto the step of our ride along mower and died. Sick and heartbroken I filed a police report and they cited the owners and it's a misdemeanor here in Utah. He protected my hens who lay eggs in the barn. We need strict laws that fine the owners when their dogs come onto your property and kill your animals. We have a 100 ft driveway and 5 acres. These dogs are nuisance animals. The Sheriff said to call anytime they are loose off their property, our next door neighbor. Our rooster was an integral part of our flock. He was raised from a chick with ten hens and another rooster.They are four this year and he will be missed.
Laws are made for those who abide by them... not those who don't care unfortunately. Maybe your neighbor will learn their lesson from the misdemeanor which still does carry a fine... or maybe not.
I am sorry for your loss. Definitely sad to see good roosters go.