If you live in Hoboken, you’ve probably joked at least once that there’s dog poop everywhere in the aftermath of the New Jersey tundra this winter. It’s one of those local lines people say half laughing and half serious. But when you really think about it, that joke points to something real. This town has a huge number of dogs packed into a very small space. A lot of dogs, a lot of owners, a lot of walkers, all sharing the same few miles of sidewalks. That’s part of why the r