When chickens go to sleep at night, the mice take over and eat all the chicken food that they want. The snakes show up to eat the mice and then they tell their friends, and more snakes show up. Eventually you end up with a year like we had with over 40 snakes killed by myself, my wife and my mom, combined!!!! Fortunately, that's when the cats showed up. Just one pregnant calico that somebody dumped. She had her babies and started hunting. Then her babies started hunting. Then a boy cat showed up, and she got pregnant again, and some of her babies had babies. By the time we had 20 cats, the mice were gone the snakes went somewhere else to hunt mice.