undercover in a slaughterhouse
An example of excellent journalism.
You can only read the original Harper's Magazine Piece, The Way of All Flesh, if you are a subscriber. But here is Ted Conover being interviewed about the story on NPR's On the Media: http://www.onthemedia.org/2013/apr/19/going-undercover-industrial-slaughterhouse/.
And here is a post he wrote on the Harper's Blog: http://harpers.org/blog/2013/04/on-meeting-our-meat/