Abstract: There is disclosed a device for chopping-up bulk material and particularly long stem animal feed material and which comprises: a frame; an elongate cutter body mounted in said frame for rotation about a substantially horizontal axis; cutter blades mounted on the outer periphery of the cutter body; an elongate housing extending partly around said cutter body, said housing defining an inlet which extends substantially throughout the length of the cutter body to admit bulk material to be chopped and an outlet for discharging chopped up material after treatment by the blades of the rotating cutter body; a feeder device arranged on the frame and operable to support and to feed the bulk material to the housing inlet; and, a grill arranged at the inlet so as to control the supply of material to the cutter body.