gray spots on coat

Question
i have a 51/2 yr old male boston terrier, and in the last month or so he's been getting gray spots on his coat, is he sick?  He acts like his normal self

Answer
When the black hair turns gray, there is a problem within the hair follicle.  If the dog is not losing hair in these areas, then it is not serious. If you want to know why this is happening, then your vet will need to take a skin biopsy of one of these areas and have a pathologist look to see what the disease process is causing the depigmentation.  SOmetimes as dogs age, their hairs will turn gray, just like people.