Back in 1972, when Atkins published his diet, the push to beef feed lots and battery caged hens was just beginning.
He didn’t stress the importance of seeking our quality in the foods he recommended, because the quality of ordinary foods was nowhere near as bad is it is now.
You sya that because you grew up unaware of how your food was produced. While beef feedlots may predate caged poultry, both have been around much longer than you realize, and much longer than the oldest Freeper has been alive.