I'd photograph it and call the authorities be it a health officer or police. I once had the neighbor from hell. I tried to ignore him but he kept escalating the harassment. Got to the point where I feared for my safety, not just my animals.
He had trip wires and spotlights all around his property. The coyotes would howl and he would call the police on me. His yard was spotless but at my edge he would put a bowl of antifreeze. One morning I was working in my garden and he started cursing me out for watering the flowers. This went on for years. Another afternoon I was out in the yard with my then toddler daughter and I saw him marching over. I figured he was going to curse me out for some imagined sin and proceeded to dump rat poison all up and down the property line. That was it! Called the police. Local cops didn't quite know what to do but fish and game had responded as backup and they forced him to pick it up or be summonsed. He was out there on his hands and knees until well after dark.
Another time I was working with a young horse in my yard that was very spooky. My girlfriend pulled up into the driveway and the horse really started a fit. Neighbor suddenly appeared with a rifle and had it pointed our way. No idea if he was planning on shooting us or the horse. I put the horse back and we went inside. Again local police did much of nothing but tell him to knock it off.
He complained about the sound of children playing. He complained about birds singing. He was a fruitcake. Was never so happy when he moved. Wasn't far enough, just down the road a mile or so but he did the same thing to his near neighbors there.
I'm actually about 5 miles away from him now and he still occasionally drives by and I can hear him make his truck growl as he peers into the yard looking for something to complain about. I often wonder when I find my fence down for no real reason if it's him trying to start something again.