The title says it all maybe a rare drop like an enchanted rabbit's foot, and these could be Like super turkeys, possibly only spawn them at easter?
Perry_Stahlsis made the suggestion of having enraged chickens in the nether but I prefer the idea of Nether Bunnies. These would be similar to Super Turkeys and other enraged beasties and would appear at Easter or Halloween (rare chance instead of a turkey).
There are the evil bunnies in vanilla that are a reference to monty python, I'm sure it would be very simple for a developer to change the stats of those
