Adjust head/eye position to stop suffocation

Basicly once i made a hamster mod and while making it i discovered that would suffocate if it was under a block even though it was less than 1 block and going into F3 i could see that the head/eye position was the same as zombies and players, this is a big issue because if you make a mob that is bigger or smaller than 2 blocks it will walk though 2 block gaps if its bigger than 2 blocks or suffocate under 1 block if the mob is less than 1 block high