A few years back, I was given a tour of a big chicken ranch and noticed off in the distance very colorful hills, ~20 ft high. Upon inquiring what they were, I was told it was old cereal that they use to feed the chickens. Not even the healthy cereal, but rather fruit loops, captain crunch and such.
It only took a short amount of time after that before I started sourcing my meat from a local butcher who lists the farms and feeds of all the animals sold.
That is crazy, my stomach turns just thinking about it.