Retrieve you game cameras from out in the woods. I think in a lot of states the law specifically allows a livestock owner to kill a dog found running loose after a previous episode of harassing the livestock, as long as the dog's owner was notified about the earlier incident.
Hopefully this will be resolved. I can't add anything that hasn't already been said and hopefully hitting them in the pocketbook, maybe they will get the message. There is another recent thread by a byc member that recently went through the same thing and she recovered the damages and then some...
I hope you took a lot of pictures. If you see the dogs on your property again get a picture.
It's been several years ago, a BYC member was being plagued by a neighborhood dog. As I recall she did talk with the owner and he denied it was his dog so the next time it came on her property and went...