As already stated, they will continue to grow up until about 2 years old. At six months, there will be a variance in their weight. Jake is almost 7 months old and is a very big boy at 27" tall at the shoulder and just shy of 80lbs (his mother was normal but his father was very large). As for the runt of the litter, that is also no indication. My male shepard (he picked me out) was the runt of the litter and when he grew up, he was huge at over 120lbs. My take is that I will love them however they turn out.