Rabbits hopping over fences

Sometimes rabbits will jump over fences.

Steps to reproduce:

1. Build a small fenced in area
2. Spawn in or capture some rabbits
3. Breed the rabbits, while not being in the pen.
4. Make sure you are in survival mode (/gamemode survival)
5. Move around outside the pen backing away.
6. Watch as some of the baby rabbits will jump over the fence.