A bunny will grow when eating a bush or a grown carrot, corn, or tomato. Try this in the "Pirate's Plunder" level. At the far right side of the level are two tiny bunnies, two normal bunnies, and some bushes. The bunnies usually try to walk or jump away from you. Be patient and use some skill to lead one bunny to several bushes Go to either of the two levels where you can grow vegetables and lead a bunny to eat them.