For size, there are no guarantees until the puppy is full grown. The most experienced breeders/exhibitors here have posted that many times.
Weight at birth does not indicate adult size.
My boys are full brothers from different litters. They are both bigger than their parents and considerably larger than their littermates.
Personally, I would wait until 12 weeks to commit to a pup, but I know that can be hard with a breeder whose pups are in demand. If I wanted to guarantee size, I would look for a show breeder who has full grown dogs that were held as potential show candidates. They release them to pet homes when then don't pan out.
__________________ Kristin, Max and Teddy  |