At what age can chickens hold their own with cats? I've heard that cats can kill chicks, but what age chicks? I read that rats can no longer kill chicks once the chicks are about 6 weeks old, but cats are bigger than rats. My adult chickens hold their own with the cats, and scare off the cats, but I'm wondering at what age I won't have to worry about the chicks getting killed by the cats. My chicks are now 7 weeks old.