The Ganmain Haystack display centre explains that chaff cutting was originally done with a reaper and binder using a team of 6 horses. The first binders were 6 foot machines and ground driven.
Later they were powered by tractors. Chaff cutting in the early days was a labour intensive industry, chaff being the major rural industry for over 100 years.
For more information on the cutting and stooking of hay in the early days try exploring these links:
http://www.ganmain.net.au/uploads/files/workbooks/Sheaf_Hay_Centre.pdf
https://en.wikipedia.org/wiki/Stook