Minecraft 360 Animals despawning?

Since the latest update I have created a Chicken coop and a small fenced pasture for keeping animals and breeding. Both are fenced one high (as a fence counts for one and a half blocks) so the animals cannot escape. I saved my game with 8-9 chickens and at least a dozen sheep lured into their respective areas with wheat and seed. When I loaded the game I had no sheep but I had a pig and only two chickens. Help? I also notice in my fenced in wheat field that animals are constantly appearing in there since the update, even if I just go inside and access a chest and return outside sometimes as many as 3 more animals will have literally appeared in my wheat field, the same is true for my animals disappearing from my pasture. Ill go inside and access a chest or leave to a neighboring village and they'll disappear from my pens. Any idea whats going on? Its become very difficult to maintain my wheat fields as the spawning animals are constantly trampling them (they spawn numerous and often enough that game has become unenjoyable at this point). Im trying to maintain, cows and sheep for wool and meat and no matter how many animals I lure and breed upon loading my animals are gone, if I leave the area even a mere 70 blocks, they vanish. Do I need to go higher on the fence? (minecraft wiki stated fences are 1 1/2 blocks high and that only spiders and cave spiders can scale them) If I go higher then how do the gates work? (mobs can pass through double doors, is this the same for stacked gates? Im trying to fence in the animals and wheat, light it torches so I can work the fields safely at night AND that gathers mobs on the fences allowing me to eliminate them later, relieving them of rotten flesh for my dogs, arrows for my bow, and gunpowder for potions). So to top it off, I would like to know if animals de-spawn or if somehow, someway they are escaping my fenced enclosures... if they are how do I stop it? (i cant say if this was an issue before the update as animals didn't follow you with wheat and werent allowed to breed) Is there a way to keep animals from spawning inside my wheat fields as this wasnt an issue before the update? Do animals despawn? I should note that post update the sun rises and sets in different areas (if you say sun rises east and sets west, it now rises from the South and sets in the North). Please Help, I found the game very enjoyable before the update and was excited for the new stuff but at this point I've discontinued playing the game as I spend all my time re-doing wheat fields and chasing animals that shortly after cease to exist. (you cant really explore without wheat, its the most readily available food source in the game, since I cant make a lot of bread I cant really explore, plus leaving ruins my animal pens) Please Help ( Adding the items per creative mode is not an option... What would be the point of playing if I did that?)