Help the Crazy Birds to defend themselves! The pigs want to expel the birdies from their own land and did set up fortresses already. But these birds wouldn't be known as Crazy Birds, if some walls could hold them back! Whether it's wood or stone, for those birdies it doesn't matter, as they just dive into the walls head first and crush them.
And if they fail there always even crazier birds to follow. Use the different abilities of the crazy birds to defeat the army of enemy pigs. Set up the slingshot and get ready to aim, shoot and destroy all the enemy structures and angry pigs.