MADISON, Wis. (AP) - Federal prosecutors have dropped four extortion charges against an animal rights activist who was accused of freeing thousands of mink from farms around the Midwest. Prosecutors said they were forced to act because a Supreme Court decision changed the legal definition of extortion while Peter Daniel Young was on the run. The ruling found someone must actually take something from another person, authorities said. The surprise move shocked the owner of a farm where authorities said Young helped free 300 mink in 1997. "You've got to be kidding. Unbelievable. Unbelievable," said Alex Ott, owner of Ott's...