There have been several here. One, in the neighborhood, was a large dairy operation and had the local Ag University set them up with a grant for composting machinery. They had a piece of equipment that went on a large tractor. It ran out the rear on the right side. It scooped the compost and turned it to the right, so the compost now was in the space previously left for travel. The process took several months with a turning a couple of times per month. If you were able to get it when it was completely finished and not a little green, it was very nice stuff. Had a very earthy, clean smell and feel to it. Not sure what it tasted like, as I usually spit it out quickly.
Cow compost is usually cleaner than horse, I think this is due to the cow's two part stomach. The horse compost will bring in a lot more weeds. Both need to have a hot compost, where the pile will aerobically heat itself to about 140 degrees F.
Hope you can make an economic success of the project.
Kevin