The Horse Studio is still currently rolling out to farmers, but once you receive it, you'll be given a blank horse template costing anywhere from 20-25 Farm Cash as-is (the final price is still unknown, as Zynga works on "Price Testing" the feature). Each time you add a new feature to the horse (say, wings or a tail), the Farm Cash price will go up. You can change the color of these items, and can add sparkles or other effects around the horse to make it more unique. Ultimately, you can toy around with your created horse as much as you'd like, and can then purchase it to place on your farm for the final Farm Cash price based on your design. That is, if you create a horse with 50 Farm Cash worth of decorations or "upgrades," you'll need to pay that much Farm Cash to actually own the horse.
Unfortunately, since there are thousands of combinations available for features here, the created horses can't be bred into matching foals, and players on the FarmVille forums are reporting that these animals can't be placed into Paddocks or the Horse Stable either. While the horse can be harvested, you won't earn mastery points, making this more of a glorified farm decoration than an actual horse. Still, if you've always wanted Zynga to release a horse with specific features or colors, you can skip waiting and simply create one yourself.
What do you think of this Horse Studio feature? Will you splurge dozens of Farm Cash on a horse of your own design, or would you only if it could actually be bred? Let us know in the comments.