A plan to move Agriculture Department researchers out of Washington has thrown two small but influential science agencies into upheaval. Federal employees at the Economic Research Service (ERS) and the National Institute of Food and Agriculture (NIFA) have quit in unusually large numbers since August, when Agriculture Secretary Sonny Perdue announced he would relocate the offices. ERS leadership has been conducting final site visits this week of candidate locations, and an “announcement Friday is very likely,” said Peter Winch, an organizer for the American Federation of Government Employees, a union that represents ERS workers.USDA declined to say when it will announce the new location for the agencies. “We don’t undertake these relocations lightly, and we are doing it to improve performance and the services these agencies provide,” Perdue told The Washington Post in a statement.