To this day in Salinas—home of John Steinbeck and one of the wealthiest cities per capita in the United States—has an area surrounding it known as "The Salad Bowl of the World" with a $2 billion agriculture industry.
Migrant workers in the 1930s picked fruits such as grapes, peaches, figs, and apples. Vegetables such as peas, beans, broccoli, cauliflower, artichokes, and celery grow there as well. During the Depression, jobs picking these vegetables and fruits were often performed by women and children, as well as men.
In addition to these fruit and vegetable workers, there were farm labor migrants who rode the rails and harvested wheat and barley all the way from Texas to Canada in the first quarter of the twentieth century. But much of the harvesting of grain in California was performed by men who migrated from within the state.
The characters on the ranch in Steinbeck's Of Mice and Men resemble these men who work one ranch, then go to another. The economic collapse in the 1930s stopped the production of mechanized combine harvesters, so the work was done with horses or mules and laborers. In Steinbeck's narrative, Slim is the muleskinner, and he is quite skilled. Crooks is the stable hand, who takes care of the mules. He is involved with their feeding, hoof care, and shoeing. He also takes care of the tackle: the halters, bridles, reins, harnesses, jerk line, and so on.
The other workers are much less skilled. Candy, the old man who is called a swamper, does odd jobs around the ranch. He sweeps out the bunkhouse and mops and cleans it. The ranch hands work in the field, loading the bales of hay that are made, or they load the bags of barley. In chapter 3 Slim notes that Lennie nearly killed his partner loading the barley. "There ain't nobody can keep up with him. God awmighty I never seen such a strong guy," one of the others remarks.