The book Animal Factory, by David Kirby, takes a close look at factory farms and the problems they cause. In an interview with Time Magazine, Kirby talked these farms and the appalling lack of government oversight.
Among the problems Kirby notes:
“... you're often no longer feeding animals what they're genetically designed to eat. CAFO cows eat a diet of milled grains, corn and soybeans, when they are supposed to eat grass.
The food isn't natural because they very often put growth hormones and antibiotics in it. That becomes a problem when you put that manure on the ground.”
Animal Factory also looks at the fate of the Neuse River in North Carolina, where waste runoff from pig farms caused massive fish die-offs.
Sources:Time Magazine April 23, 2010
Read all of it.