As job requirements go, these are unusual by most standards. Candidates must complete a rigorous six to 18 month-long training program, possess the skill and experience to spread joy wherever they go and, yes, have a wagging tail. That’s just some of what it takes to become a service dog for the Dunkin’ Joy in Childhood Foundation’s Dogs for Joy program. In August, three cute canines checked every box, and made their debut as full-time, in-residence, service dogs at hospitals across the country.