According to the press release announcing Kevin James as Otis, "Barnyard" will tell the story of what happens on a farm when the humans in charge are not around. The saying "party 'til the cows come home" takes on a totally different meaning as the cows themselves are the ones partying. Unbeknownst to humans, barnyard animals can talk, dance, sing and even play jokes.
James' character Otis is a total party animal who failed to inherit a sense of leadership or responsibility from his dad. But when Otis is suddenly forced to be in charge, he has to find the courage and confidence to lead his barnyard buddies.
Source: Nickelodeon and Paramount Pictures