Is my new labradore unhealthy ?

I just got a labradore puppy but he is only 36 days old , i looked at the images of labradore puppies on internet and my puppy looks so much thin then those puppies,and he is small in age but he bites so much and sometimes bark at family members when given a light pat as a punishment for biting , should i be worried and do something about it or he will get rid of this habit when he'll grow up, i added a link with his photos. http://imgur.com/a/31wa2

 

Moderator Note:

Sadly, in some parts of the world there is a tragic trade in tiny puppies barely able to walk. On the Labrador site we frequently get comments from people who have purchased puppies as young as 21 days old. Their owners will usually need help from a qualified veterinary professional if the puppy is to survive and thrive.

Our forum policy is to encourage people to wait until their puppy is eight weeks old before collecting it from the breeder. To make sure we are not encouraging the trade in underage puppies, nor depriving these puppies of essential veterinary attention, we have the following rule.

If a forum member’s puppy has been removed from the breeder/ mother before the age of seven weeks, that member must wait until their puppy is seven weeks old before posting about him or her on the forum

We recommend that anyone with a puppy under this age contacts their vet without delay for instructions on feeding, general care, and medical treatment. We understand that members want to help these puppies, but the forum is not the right place to be distributing specialist advice of this nature.