a system includes trays of a plurality of different widths and an unloading system for unloading cartons from the trays . the trays each comprise a base and a pair of end walls extending upward from the base . the unloading system comprises a plurality of fingers . each of the end walls comprise a plurality of vertical slots open to an upper edge of the end wall . the fingers are positioned and dimensioned to pass through the slots of the trays as the trays are delivered by the tray delivery conveyor to lift contents of the trays . the fingers are positioned so that some fingers pass through the slots of each of the different widths , but others pass only through slots of wider said widths .