For this product you will be competing with stuff like the dog sled. Those exist with wheels already, and at least one dog can rest on the sled if it is not already in use.
The dog sled is a very simple design, and I expect it would be hard to improve considerably on it. Trust me, you would not be the first one to try to improve on such a design.
to repeat the insight: humans can cover more distance with a bicycle than walking, likewise animals should be able to do so if a machine is designed for them to power like w/ pedaling
You "invention" reminds me of Jimmy Speckerman's invention: glasses that show non-3D movies in 3D. In both cases the idea is trivial, many have thought of it, but practical problems
are hard to solve satisfactorily, and the "inventor" wants someone else to do that part, as if that was just mere trivial implementation details. In reality that is the hard part.
However, still, there could be good new ideas. A nice parallel would be the "instant Legolas", which for some uses improves on another old and tested product: bow and arrow.
