Back at the Barnyard S01 E38 School of Otis

Otis must take over teaching (in the stern of Bessy) after accidentally injuring Peck, the children's teacher. When he realizes that the kids learn boring things, he teaches the kids how to pull pranks. However, the kids develop an ultimate prank, which sends the barnyard silo to mid air, just when all of the animals are in there to hide from Duke, who appointed himself as new leader.