I often took my turkeys on foraging walks with nothing more than a stick. They had a ball going after the grasshoppers.I wanted the harness so that I could take the turkey outside of the yard, without the risk that something might spook her and cause her to fly off into the distance.
Turkeys have tapered necks and rounded bodies, whereas dogs are more cylindrical. I don't know, I could not get a dog harness to fit comfortably on a turkey.