Monsters that cannot path to you will no longer keep you awake! That Zombie right outside your window can't keep you from having a good night's sleep!
Animals will now eat dropped items off of the ground, given that they are of the same variety as the animal normally breeds with.
Animals will now give off barrier particle effect when they cannot eat. This is changed from villager particles in 1.7.10.
An Example of one of the states of Chunk Boundaries added by JWIN.
Another example of the chunk boundary overlay added by JWIN.
An example of the Mob Spawning Overlay added by JWIN.