Abstract: The disclosed machine is for shredding cylindrical hay-bales. The machine is provided with knife-type (as opposed to flail-type) shredder-blades. The blades (52) are mounted in a rotating cutter frame (38) which is positioned parallel to, and alongside, the hay-bale (34). The shredder-blades are pivotable on the frame, and fly outwards, ready for shredding, due to centrifugal force. A set of drive-rollers (43,45) rotates the bale past the blades. The shredder-blades are presented edge-on to the cylindrical surface of the bale. This presentation of the blades gives great efficiency and economy of shredding.