WWI promotion for backyard chickens
WWII brought higher prices, and not a collapse afterwards
during the war fewer farm workers grew more food, mostly by working more hours (and young teenagers working during harvest season)
more and more farm families depended on outside jobs

production controls that you could only grow tobacco on an allotment of acres on your farm prioritized yield
the government kept up price supports for 10 years
when your allotment could be sold to someone else more farmers moved out of full time farming
farmers couldn't make enough money to support increasing expectations of consumer goods
why was it so hard to make a decent income farming?

large scale production made food cheap enough that growing and canning your own food at home was mostly not worth the effort--people gave up their hogs, chickens, milk cows, orchards...
plus refrigeration and freezing

his brother-in-law's story:
to make a living from a farm you had to get bigger and bigger to afford the necessary specialized machines