Ever wonder how puppies grow? Short answer: From the outside of their bodies in; meaning that their feet, ears, tail and muzzle reach adult size quickly. Look at the picture here. This puppy appears to be around 12-weeks old but compare the size of his feet to his mother’s. Compare the first joint on his leg to his mother’s. They are darn close. And by about five-months old they will be nearly the same. As will his ears, snout and tail.
He’ll then spend the next five or so months elongating in other ways so by around ten-months of age he’ll be almost as tall as he’s going to be.
Weight is a slightly different matter with the rough estimate for this being 2x their 4-5 month old weight. So, 25 pounds at 4.5 months means around 50 pounds at adulthood.
This is an extraordinary amount of growth. Imagine that you were born in February, half your adult weight by June/July (with your hands and feet being almost adult size)and then the size of an older teenager by Christmas. This is why pups sleep so much; they are growing so fast. The bigger the dog will be, the more they sleep those first months.
As a general hint: Any time your puppy gets cranky, snarky, sharky, or frantic think “nap” before you think “bad”. Just like children, pups can get over-tired and over-tired brings out the worst in everyone. And, please, use a crate for nap-time so your pup can get the uninterrupted deep sleep that is so needed for this amazing transformation.
Now you know how puppies grow.