Wow, I'd be steaming mad! This is good advice, all the above. Two things about this kind of situation that I've both experienced and watched others go through in various states:
1) Document, document, document. Take notes, take pics, make sure you post a complaint with your local sheriff's office. That way it's on the record. It's not enough just to be in the right, you need to think of possible litigation if you do end up defending your livestock and property. People are crazy these days and everyone wants to sue for every little thing.
2) This is just my experience. But in Arkansas, where I lived for 6 years, the local sheriff of our community told me about their unspoken law there: "Shoot, shovel, shut up". I'm not advocating this explicitly. But we had to do this after a pack of wild dogs showed up and attacked local animals, then our own. We shot the lead dog, buried him immediately, never said a thing. No one came looking in this case because they were feral.
Lastly, when I lived in Idaho one of my dogs--a beautiful Siberian Husky-- attacked and killed a neighbor's turkeys and their pet duck. I put the dog down that day. Took him to the vet, explained the situation, and the vet told me this was the right thing to do because once they've attacked something, they'll continue to look for opportunities to repeat this behavior. We didn't get sued but if we had, I was on record as having responded immediately and taking responsibility. It was hard. But it was the right thing.