Affects Version/s: Minecraft 1.8.1
Fix Version/s: None
If you have a pen of rabbits, go outside one corner, and then take out dandelions or carrots, some of the rabbits may get stuck together in the corner. At least around ten rabbits are needed, and the size of the pen doesn't seem to matter. It may take a few tries to get it to happen.
The most pronounced effect occurs when fences are the pen's boundary. With walls, they don't seem to get stuck in the corner, but they get slightly stuck together at the walls. With solid blocks, only babies seem to get stuck, though more stuck to the corner than stuck to each other.
Once stuck, the rabbits cannot move horizontally—only rotate and jump. If carrots are taken out again at the other end of the pen, the stuck rabbits will jump up and down like they normally do, but they won't move from the corner. With lots of rabbits, some will start rocketing out once the food is removed. With walls, they seem to get slightly stuck together against the sides of the pen and display some of the same behavior. However, any interaction with them, including pulling out food from the other side, will get them unstuck.
Quitting and returning does not get the rabbits unstuck, nor does pushing against them or hitting them. However, removing the blocks beneath them or removing the corner piece and pushing against them from that corner does.
I've also noticed with this than rabbits seem to have an affinity for the northwest, but I'm guessing that should be brought up in another ticket?