The story
Popularized by (and perhaps coined by) Earl Butz, a U.S. secretary of agriculture in the 1970s.
Etymology from Wiktionary, CC BY-SA 4.0.
get big or get out
Today it means: An exhortation and admonition to family farms as businesses, or to other businesses in other industries, that they need to either expand their operations and capitalization or be outcompeted (by those who do so) and thus go out of business. Full definition →