The Iowa farmer's home hog market was growing more favorable compared with Chicago in the years which immediately preceded World War II. Price differentials or spreads, when measured on a yearly basis, were tending to narrow between Chicago compared with two Iowa interior packing plants and Sioux City. Figure 1 brings this out clearly.
Thompson, Sam H.
"Iowa's Hog Market Improves,"
Iowa Farm Science: Vol. 1
, Article 7.
Available at: https://lib.dr.iastate.edu/farmscience/vol1/iss3/7