DITTO!Maybe I've just been lucky, but I've had a pretty good read on mine by 8 wks. I watch how they approach new situations/scenarios--- whether it's outside for the first time, and who is eager to go explore in the garden (cover), under the deck, under the shrubbery, to the field, the front steps (my nightmare, actually) etc.. I watch how they respond to new rooms in the house, and may have a temperament test done by a stranger in a new environment at 7 wks. I have a friend help me test them on live pigeons at 7 wks. I won't pick my own until after vet well checks and CERFs as that's another evaluation opportunity (and what if a problem were to be found?). I start looking at movement and structure as early as 6 wks, but watch to see who stays together thru 8 wks when we do the final evals for conformation. I want the whole package and honestly think it can be done. I also narrow the choices down for my buyers and so far, so good. So I think it depends in part how much time the breeder is spending w/ the litter actually watching the pups and trends.
Maybe we're kidding ourselves, but I think I have a good take on my pups at eight weeks, but it takes a lot of time with the pups!
A puppy buyer who thinks they can spend an hour watching a litter and make an educated choice is really kidding themselves. Best to tell the litter owner what you are wanting from the pup and let them direct you to the couple of pups that best fit your needs.