Pets can benefit from training, boarding and day care owned by a veterinarian—the DVM is the expert, after all, not pet service and pet retail staff somewhere else. Just figure out if this chance for pet enrichment for your clients is the right fit for your veterinary hospital's philosophy, staff and location.
When veterinary clients pay an annual fee—or monthly installments—for wellness services over the course of a year, will they be mad if they don't use them? Not if you remind them. (You ARE sending out regular reminders for everything, right?)