Have you seen “Food Inc.”?
It was very tastefully done (pardon the pun), and I would have to say that anyone who watches it will think twice before purchasing a chicken (or anything else) from a grocery store again.
I know that it is available on Netflix, and you should be able to get it at your library. If your library doesn’t have it, don’t be afraid to ask for an interlibrary loan it for you–wait a day and it’ll have it for you!