When a recipe calls for a chicken breast, chances are it's actually referring to a chicken breast half. A full chicken breast, rarely seen at the grocery store, would include the two halves connected by a breast bone.
You'll usually find chicken breast halves packaged either bone-in and skin-on or boneless and skinless. Bone-in chicken breast is best suited for longer cooking methods, such as roasting, braising, and barbecuing. Skinless, boneless breasts takes well to the sauté pan and the grill.
Chicken thighs can make a good substitute for chicken breasts, though they may take a little longer to cook.
If your preparation includes the skin, such as a stuffing that will go beneath it, look for pieces with the skin well intact with no rips or tears. For boneless chicken, look for pieces about the same size so they will cook evenly. Buy the best quality chicken you can afford.
Trim away any visible fat and excess skin, if the breast is skin-on.
Keep chicken refrigerated or freeze for longer storage.