In a large complex, owned and developed by a multi-millionaire with a pioneering mind, a institute was created to help train and develop the minds and forms of people to fit certain roles. These roles are designated and designed by leading experts to make the person undoing the training, to become a certain animal in mind, and try to develop their bodies to better fit the role they've been trained in. Through mental conditioning, and various chemical and bioengineering procedures, the institute has been able to do this successfully thanks to the funding provided by it's founder. The companies name, ReDev Animals.
On the outside, the company advertises itself as a place to train people to learn how to handle animals over a week long course, and for the most part, that's what it does. However, sometimes they'll get people paying to buy people that have been conditioned under the special course. Sometimes it's eccentric buyers wanting interesting pets, sometimes it's a jealous ex that wants to get back at their former spouse and requesting they get conditioned. Either way, unless a target is specified, the institute will choose one person on the regular course, to undergo the special course.
The special course itself is a week long process. Involving multiple conditioning workshops and body modifications. The end result isn't a complete transformation into an animal, but the biology of the person has altered so much that they have multiple features of the animal. If say a woman was trained to become a cow, then their skeleton would be permanently changed to be quadrupedal, their breasts would increase in size and they'd grow a second pair as well, and their anatomy would be not too dis-similar to a regular cow, SO much so that they'd even have viable offspring with they mated with a bull.
This time round, the ReDev institute has gotten a request. And the request target this time is...