I can't believe anyone breeding would keep a whole litter! Total madness, why did they breed in the first place - perhaps it was an accident? They can't possibly have given all the pups the attention they needed.
I have only ever bred to have a pup for myself or a close friend, and only ever kept one - far too difficult to train to together, as said above, they bond with each other.
To be honest my two oldies have done that - I had Allez at 9 weeks, and Belle the week after but she was already 2 years old. That said they have been easier to train to the gun because she was already trained to BoPs.