Ingredients 3 pounds small boiling potatoes or medium sweet potatoes, cut in half 8 quarts littleneck or cherrystone clams 12 ears corn, husks on 2 pounds red or yellow onions, peeled and cut in half 8 quarts mussels, well-rinsed and debearded 12 chicken thighs (optional) 3 pounds spicy sausage such as chorizo, linguica, kielbasa or andouille, cut into 4-inch lengths 12 (1-1?? pound) lobsters, liv