a machine for stacking hay bales emerging from a hay baler in pyramidal stacks of six bales , has a supporting bed for receiving bales from a drop table . the bed is provided with a side panel and a pair of separator panels for separating rows of bales in the stack , the dividers being tiltable for orienting the bales into a pyramidal stack . the machine is mounted on wheels for towing , with the bed being pivotable from a substantially level position wherein the bales are collected , to a rearwardly dropped position for discharge of the bales onto a field in a pyramidal stack . improved discharge of pyramidal stacks is achieved by orienting the separator panels at an oblique angle relative to the line of travel of the machine whereby slippage of the bales from between the panels is facilitated .