Residential or business directories may contain sub-directories of specific occupations after the “main directory.” These directories may contain additional clues about your ancestor. Don’t just find your ancestor once and quit.
There may be smaller directories in the back.
The illustration shows a list of Silver-Laced Wyan-Dotte chicken breeders in Hancock County, Illinois, in 1918.
Look in the back. Don’t be chicken <grin>.