I will present to you a small mod: The Attack Chickens Mod!!! This is a small mod that adds hostile chickens for you to fight. WARNING! They can clog caves! Anyone may use this mod in any modpack they want.
As a warning... DO NOT put this on a public server or install it to your main world. It will cause numerous issues and possibly a world reset. I have removed the mod due to millions of chickens spawning uncontrollably and now I'm having chunk errors and some of the existing blocks in the world (ie: TE Item ducts) are having issues and causing client crashes now.