Whispers, what we sometimes call a Jenny is really the Cat mill. Believe it was Carver that hung the name swinging jenny on the cat mill. Regardless the cat mill or swinging jenny is powered by the dog running on the ground after a live bait in a cage or more preferably a animal hide etc.

The Horse Jenny that most Horse persons use have over head arms to attaché the horse leads to. Apparatus is powered by a electric motor. Usually designed to walk more than one horse at a steady horse walking pace.

Your friend may be a right on person. But would not expose my dogs to maybe his friends. Met very few horse lovers that liked dog men that owned any type of sporting dogs. The Humane Society and Peta are always just one phone call away.

You can do better with that type of mill work out with a electric tread mill inside of a building. Cheers