Will you only be breeding your monkeys for use in your delivery service, or will they be available for purchase? I had a capuchin monkey for a few years as a kid, and I really miss the little guy.
First, contrary to some conjecture, these monkeys are not flying out of Oz. They are flying out of, well, somewhere else.
As regards pethood, you have to understand that these are highly probabilistic monkeys and are governed by the well-known Uncertain Monkey Principle. As such, while they make great delivery agents (they can be anywhere at anytime!), they just won't sit still or respect metaphysical boundaries and people have found them to be lousy pets.