Vegetarians and concerned carnivores alike have long protested the way livestock is raised at many large farms. But it's taking some time for Americans to view this not only as an animal-mistreatment issue but one that directly affects human health. The Union of Concerned Scientists has taken the issue up, and is driving its point home by citing a recent event in which rural Minnesotans actually fled their homes as a result of animal crowding's side-effects.