Less than a hundred years later, only 4 percent of farms had chickens

In 1900, diversification (at least on some level) was inherent in agriculture; 98 percent of farms had chickens, 82 percent grew corn, and 80 percent raised milk cows and pigs. Less than a hundred years later, only 4 percent of farms had chickens, 25 percent grew corn, 8 percent had milk cows, and 10 percent raised pigs. And, in may cases, the farms producing these commodities did so exclusively.

D. Barber, The third plate (2014), 74