I actually didn't think it was as shocking as it could have been. I've seen photos of WAY worse battery farming conditions than they showed in the henhouse. It wasn't luxurious, but it could have been worse - DD, who's two, said "Chickens!" with delight and didn't seem to think anything was amiss.
The movie is pretty lame compared to The Omnivore's Dilemma, IME. It referenced a lot of the same facts and people, and while it was cool to see Joel Salatin in "real life" and see the visuals of his farm, I felt a bit been-there-done-that the whole way through the movie. And the way it was structured, in "chapters" that weren't very connected, made it seem really piecey and a bit ranty. Like "Oh yeah, you're supposed to be mad about this as well!" It crammed a lot of stuff in - Monsanto, meat processing plants, corn and so on - without going into any subject in enough depth to satisfy me. It hinted at government conspiracies and then rapidly moved on... stuff like that.
So if you haven't read any of the other eco-foodie literature it might be an OK intro (although a friend of mine hasn't, and even she thought it was sketchy and underplayed the animal cruelty issue).... but if you're already familiar with some of the books, the film is a waste of time, I think.
It didn't upset DD, but she's a bit young to get upset. Try to look up some clips from the film on YouTube to see if you can gauge the gore/upset factor for your kiddies.