Sorry for your losses. I find it hard to believe there are no regulations about dogs running at large, dogs fouling other people's property, harassing livestock, killing livestock, etc, etc. I think animal control...ok the sheriff just doesn't want to enforce the law cause it was only a chicken & duck but your pets are just as important to you as that **** dog is to it's owner. Seems to me a dog that would kill livestock may be a threat to a small child given the right circumstances. You can probably find the local ordinances online, look em up. Sounds like the other neighbors have had enough of this dog to band together, pay the owner a visit, tell him if he doesn't control his animal you're flood the sheriff with complaints, then follow through. You're having to go above & beyond to protect your birds, it's costing you time & money to do so, the burden needs to be placed on the owner of the dog. Stay on that guy till he takes care of his mutt.