Why does your Yorkshire Terrier constantly nibbles top of his back legs?

Your Yorkshire Terrier may nibble at the tops of his back legs due to a variety of reasons, including Allergies, irritation, or boredom. It could be a sign of skin issues such as fleas or dermatitis, or simply a self-soothing behavior. If the nibbling is excessive or causing skin damage, it's best to consult a veterinarian to rule out any underlying health problems.