Since they are sold after they reach 2 months of age, patterns start coming in. With Veileds, usually it's a ton of dots. From pictures I've seen of babies. (I like the dots.)
i have always wondered the same thing jan, i figured it was based on color (i know its not much, but maybe there's a slight difference in barring or something) or by their attitude (aggression), or even maybe by their feeding habits(like choose the one that eats the most)
You will always have stand outs that you will notice at an early age I call them keepers but you cant keep them all. Most breeders will sell these at a higher price just like any other breeder weather it be dogs, horses or reptiles.
Some will catch your eye on your normal routine. One will just throw something really great out. I am also holding onto the early birds/ the ones that grew exceptionally fast.