I built the first HoundRound giant hamster wheel for my little dog Jumbo (see other videos). I built this gigantic one on commission for large dogs (Siberian Huskies). The internal diameter of the rotating ring is 7 feet. It has a dog powered kibble dispenser (as shown here), as well as a peanut butter conveyor belt like the original HoundRound. The speed of treat dispensing is adjustable for both treat mechanisms.
