Keep in mind that I'm a country boy, I also have a lot of livestock to protect. I do not know the laws in Vt. But I know that if you have a predator on your property you have the right to protect your livestock. I'm not suggesting you do any thing serious, but I would let the person know that you will protect your livestock.
The person sounds like a irresponsible breeder, It is their job to pen theirs dogs in heat up or leach them when outside. You just don't let your dog in heat run nilly willy. Here at the homestead I'll do whatever it takes to protect my stock. Certain times of the year we get skunks, possums, usually we live trap them and then let them go far away from our homestead. One time we had a problem with a bear and our honeybees, I called the game warden and that was that.
Hoped I helped some.