Over all I would think that it is a roll of the dice but I tend to keep pups out of litters that over all favor the dam/sir that I'm hoping to gain something from. Such as if a sir is short built,red and active I will most likely hang on to the ones that have this look. Although I don't care for raising pups and much rather get a dog at the 9-13 month old range I believe when it comes to breeding if you have watched a pup grow up to earn breeding rights you have a good chance of picking a pup that follows that dogs ways as a pup. So I do believe that raising pups does help one gain a good eye for picking good ones out