Starbucks is fighting an expanded effort to unionize its stores. The effort comes even as a union vote proceeds at three of the coffee chain’s locations in Buffalo, New York. Union organizers from three additional Buffalo-area stores appeared before the National Labor Relations Board on Thursday, asking to hold union votes at each of their stores. The workers are seeking representation by Workers United. They want more say in pay and how stores are run. Seattle-based Starbucks has never had unionized workers at its U.S. stores in its 50-year history. It says its stores function better when it works directly with employees.