Remove the skin from chicken. (The easiest way to do this is to loosen the skin at the meaty end of each drumstick, grasp the skin with a piece of paper towel and pull it towards the narrow end of the drumstick.)
With sharp knife, cut 2 or 3 slashes in each drumstick right through to bone.
Arrange drumsticks in shallow nonmetallic dish large enough to hold them in single layer.
Sprinkle chicken with lemon juice and salt, rubbing into slashes; set aside.
In food processor or blender, combine yogurt, onion, garlic, gingerroot, chili pepper, allspice, coriander and cumin; process until well combined and fairly smooth.
With machine running, add red and yellow food coloring a drop at a time to yogurt mixture until mixture is a rich orange red color.
Pour yogurt mixture evenly over chicken, rubbing marinade into slashes.
Refrigerate, covered, 24 hours, turning chicken occasionally.
Remove chicken from marinade, shaking off excess.
Place chicken on oiled barbecue grill; grill over medium heat 25 to 30 minutes, turning often, until chicken is golden brown and no longer pink at the bone.