Hartz® Bird Toy. For medium - sized birds. Provides mental stimulation and helps reduce boredom. Hartz® bird toy for medium sized birds is wildly fun. Your bird will have hours of fun chomping, chewing and swinging on this exciting toy. Playing with the sisal twine can also provide an alternative activity for feather picking birds. Visit our website www.hartz.com. Hartz® is a trademark of The Hartz Mountain Corporation.