When muscles are more heavily worked, they hold more oxygen, which gives the meat a red color. Chickens are flightless birds so their breasts are not red, but their legs, which they use, are dark.
The USDA grades chicken on appearance, not fat content. Grade A means the chicken is well formed, free of feathers and has a layer of fat with unblemished skin. The same is true for turkey.
Varieties of poultry white meat include bone-in breast, skinless bone-in breast, boneless breast, breast cutlets, tenders, wings and drumettes.