The present invention relates to a rotor feeder unit (31) for agricultural machines, and more specifically to a rotor feeder unit for an agricultural baler (1). The rotor feeder unit (31) according to the invention comprises a rotor feeder (33), and a drive for driving said rotor feeder (33). The drive of the rotor feeder unit (31) according to the invention comprises an input (55) that is configured to be coupled to a power source, an output (57) coupled to the rotor feeder (33) for rotating the rotor feeder (33) about its axis of rotation (37)； and a variable ratio transmission (53) coupling said input and said output.
