Put the chipotles, adobo sauce, garlic, shallots, lime juice, cilantro, olive oil, salt and pepper into a blender. Pulse the marinade until smooth and emulsified. Rub each chicken liberally with the marinade.
Arrange the chickens on a half sheet pan with a rack. Roast until cooked through, about 60 to 75 minutes. Remove from the oven and allow them to rest for about 15 minutes. Carve 1 chicken and arrange it on a serving platter. Serve. Reserve the remaining chickens for recipes that use roast chicken.