Baby Cows Everywhere!

When logging out of a world and then logging back in, baby cows spit out of my auto cow cooker, even though there is only one hole that even a player can't jump out of. They just go everywhere, but walk up the dirt stair case I made back into the hole. They should just stay in the machine. The design I am using is http://www.youtube.com/watch?v=2AN0tv4C5AI .