A Stationary Hay Press would sit in the middle of the field, wheels buried up to the body.  An implement called a buck rake  would deliver shocks of hay.  A boy riding a team of horses would  go around and round all day powering the machine as one or two men would feed hay into the hopper.

Hay Baler at Heritage Center
A working model of a Hay Baler

See the Wikipedia article for more informaiton.

1979.009.002 Loader, Bale Hay