average size of puppy

Question
We just bought a female chesapeake bay retriever from a breeder out of country. The puppy is supposed to be 9.5 weeks but she just weighed in at a whopping 24 pounds- nearly half of what her full-grown projected weight should be. The dog is beautiful (and we will love her no matter what) but I am suspicious of the age the breeder represented.  Does this sound a bit odd?  Although this is my first Chesapeake I have grown up around Lab Retrievers (and she should be comparable in size) and usually at 9 weeks I think of the waddling football but this little lady looks like a more mature pup with the longer legs.  Any suggestions?

Answer
I would take her and her medical records to the vet and see what he says.  If she is much past 9.5 weeks, she should have space between her teeth and maybe even starting to lose the front ones.  You are right about the legs too.  Sometimes in 2 weeks they gain 5 pounds and it all seems to be leg.  I have little experience with Chessies, but would expect their development to be similar to Labs.  

Fat puppies may be cute, but lean ones grow up to have sturdier joints.  How ever old she is, she should halve a waist.  Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them.  Each dog is different.  Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx

If the vet agrees with your feelings, I am not sure what you can do.  If the puppy really is older, I wonder if you can depend on anything the breeder said.  You could also have problems with socialization.  Puppies that spend all of their first 12 weeks in a kennel often do poorly elsewhere later.  I doubt there is much you can do, but I don't have any experience in that area.