One may only throw a stone at a bird in self-defense.
Sec. 403-4. Throwing stones or other missiles. It shall be unlawful for any person to throw any stone or other missile at any bird or any animal, except in self-defense, or to throw a stone or other missile on or across any street, alley or public place of the city. (Code 1975, § 20-6)
In Illinois, animals can be sent to jail.
A monkey once served 5 days in a Chicago jail for shoplifting.