I like to do this at 6 weeks of age.  Have the pups come out on the floor and just play for a while.  You learn a lot by just watching.  Certainly good movement can be identified even in a six week old. Certain pups will carry themselves well.  You can also identify a pup that stacks himself.

While they are about nipping on your toes, it’s a good time to bring out the toys.  See who is interested – usually the brightest; who comes when called “puppy, puppy, puppy” when put further away – an outgoing sort; who relentlessly engages – perhaps the kind of pup you want to do obedience or agility work with.  It’s not all just for beauty.

There are many knowledgeable canine enthusiasts who have written about temperament and direct you to test for submissive vs. aggressive behaviors.  You can try some of these activities to learn more about your litter.

And then there is “the stack”.  Checking out how pups look while stacked can teach you a lot about structure and skeletal placement.  You can see a good front.  You can feel the point of shoulder and correct layback.  And even though rear legs are not as developed as they will be when the pup is a little older, you can see a stronger rear.  Be gentle with the little guys being manipulated and contorted.  If at first you don’t succeed . . .

Listen to what everyone has to say; everyone does have an opinion.  You can learn a lot about your litter.