i read Upton Sinclair's "The Jungle" when i was 16 & (even though it is mostly about labor, SES, & human suffering) it was the sick treatment of nonhuman animals depicted in that book that grossed me out the factory- farmed carnivore door.
Here's a great link on this topic:
Food, inc article at Alternet
Here's a great link on this topic:
Food, inc article at Alternet