Can anyone advise me on skin darkening on hind quarters, along with hair loss?

I know in greyhouds, sometimes they won't have fur on their hind quarters. Milky's has never grown back. I know as certain dogs age, there skin color may change. Also, if they are a white doggie, they have more spots show up.

The absence of hair is normal. If the dog is actually losing hair and the skin is darkening, that might be a sign of a thyroid issue. Be sure your vet is aware that greyhounds tend to have lower thyroid values (T4s) that the average dog, though! (Hypothyroidism in Greyhounds by Dr. Stack

-Shalea (my first post! )