Chipotle is giving customers something to cluck about. The Mexican grill-style chain debuted its first new chicken item in its 29-year history Thursday, the pollo asado, which will be sold at locations in the U.S. and Canada for a limited time. To stand apart from the longstanding adobo chicken option, the pollo asado is flavored with spices, seared on a plancha griddle, then cut up into pieces and tossed with marinade, cilantro and fresh squeezed lime juice. “Chicken is easily our most popular protein, with many of our most loyal Chipotle customers ordering it the majority of the time,” Chris…