Chicken rain Tutorial

Well, that was satisfying to do. The tutorial was so easy, that it was done in just a few minutes, and really fun to remove the chickens. When I started, I couldn't understand how the coding works, or where the tutorial was. But that wall is scaled and I'm already finished this thing.
So, I followed the instructions of the tutorial, then I just decided to have some fun. I raised the amount of mobs spawning to 5000. Then I typed "kill @e" which killed all the chickens in the area. And that was the most satisfying thing I've done.