Yes, sorry, there are chavs here as well as in the UK. Generally less here but they exist everwhere. Lock it up.

Dog shit all over your front door?? That's a bit extreme!
To poison an animal, that is just sick!!!! How can people do such horrible things? Reminds me of a similar experience I had when I was a kid... our neighbour killed our dog with an ax because it chased his hens a few times. He always left his hens on the street cause he hated their shit on his own front/back yard. We hated seeing the street get dirty, the constant cockadoooo but back then we couldn't do anything

That is simply go to the police behaviour. That simple. And you take it all the way. Backing down from somebody treating you like that is never an option until it escallates to the threat of physical violence or criminal activity but until then war, no retreat, no quarter given until the little shite has got down on thier knees and begged for forgiveness. That easy.