A haymaking device has a frame movable in a direction of travel and has at least a first and a second crop processing tool which are arranged side to side. The device further includes transfer mechanisms for transferring the first and second crop processing tools from an operative position, in which the crop is engaged, to a standby position, in which the crop is not functionally engaged, and vice versa, respectively. A programmable control unit for the transfer mechanisms independently activates the transfer mechanisms from each other, and processes data indicative of an angle between a direction of travel of a work stroke of the device over the field and a boundary line. The control unit also processes data on the speed of the device in the direction of travel, and activates the transfer mechanisms one after another in dependence on the data upon arrival at the boundary line.
