Chocolate lab color

Question
I have a 4 month old chocolate lab puppy and in the last week he has started getting patches of light brown on his back and tail. He is a coat is dark brown. We cannot get in touch with the breeder to ask about this. Should this happen and could it be because he is not a pure breed lab? Thanks in advance for the answer.

Answer
When a pup is born, it does not have it's adult coat in.  Over the first few months, the top coat will grow in and you might see a change in color (lighter or darker).  

It could be a couple of other things...if he's been out in the sun, the color can bleach out a bit.  Or if he's getting ready to shed, the coat will look like it's changing color in patches.  Or it could just be a genetic quirk and he might just end up with some patches.  One of my dogs has a very dark brown section running down his back from neck to tail, the rest of him is lighter chocolate.  Coat could be really dry too, with winter and furnaces on, fur can dry out.  

I would probably first do a good brushing and see if that patch strips out.  If it still was there, I would probably put in some conditioner (you can buy dog conditioning spray at most pet stores or just use a dab of human hair conditioner).  If that doesn't do anything, I would just wait and see.  

I wouldn't worry about it much though and I certainly wouldn't think that the pup is not purebred (although if you did not buy an AKC registered dog, it COULD be possible).  Stuff just happens sometimes.  I have even had dogs go gray in an area with an injury.  On of my pups got a deep scratch on the flap of his ear...now where that scratch was, he has a line of gray hair.