animals despawning

I had a animal farm at the rear of my house before the newest update for xbox(19th December 2012 update) and i had cows,and . After i installed the update i went on and breeded the animals and went in my house to create an enchanting room, then went back out to find they had all dissapered apart from 1 pig. So it seems since this new update animal's seem to despawn from pla
ces once you left .