If he is blogging about the welfare of horses and trying to be a voice out there and the people are "getting even" by doing this , I would say your blog is striking a nerve . I wouldn't stop blogging ,that is what they are wanting you to do . You're obviously threatening them with your blog and they don't like it . They probably think they can hurt you through the horses cause you won't be able to go to the law because there won't be any proof , that is where my idea can come in handy. Heck , put some cameras up around the area or something ! I am sure you can get these people , just don't give up !