I think you are thinking of TUF-Foot, or Pad-Tough. I was part of a backpacking group who hiked the Sierras with our dogs and many used one of those products. I was initially ribbed about my breed choice, but my little Sheltie out-hiked all those Labs and Aussies and carried her own pack, too! I will have to remember that the product could be used on chickens, perhaps as a preventative if bumblefoot ever is a problem.
That was my thought too. I compete with my dogs in agility, and those of us who are more serious not only stretch our own muscles, but also those of our dogs. I use those PT balance discs daily to strengthen my dog's core and I know several people with dog treadmills (though WHY in Southern California, when you can hike, walk, or run almost every day of the year). Horse racing has strict regimens for their equine athletes, so why would cock fighting be different?
While I also don't agree with cock fighting, there is something to be said for the accumulated knowledge base when the goal is not "the most eggs or meat in the shortest amount of time." When the goal is for the bird to be in the best health and condition possible for it to be considered "successful," we can surely learn a lot from these keepers.