"Of Mice and Men" is a famous novel written by John Steinbeck. Two main characters are George and Lennie, farm workers and childhood friends, who dream of buying their own piece of land.
Since they work on the farm, the term "buckin barley" refers to the process of lifting and packaging bags of barley on a truck.
For a further explanation, barley is a cereal grain used for feeding livestock or making beer.
