I agree with Dekka. But....let's take this one step further. From an evolutionary standpoint, supposin' this intrinsically shy mother dog who over comes some of her issues through training has puppies who exibit her genetic shyness and who also over come most of their skittishness and who also have puppies who repeat the same refrain. And after many, many generations, will the off spring begin to show less shyness? After all, isn't the brain influenced by hormones from the pituitary which regulate emotional response? And what causes hormone levels to change? Behavior and other environmental stimuli may cause dopamine and seretonin levels for example to be altered. Like when you force a smile, the facial muscles directly can cause the happy hormones to increase. Behavior is acting on that response. With repeated habituation, desensatization etc to humans or the triggers which create a shy response, over time won't the infulence of hormonal change on the brain begin to cause intrinsically less shy puppies to be born? I mean....look how domestic dogs probably evolved in the first place. The little dog-like animals they may have evolved from didn't likely start out being unafraid of humans. Something over time must have caused the "wiring" to gradually adapt to humans. Dogs are so hardwired to get along with humans. Just food for thought, I guess.
If this is true in humans, it is probably true in other mammals. The womb environment has such a huge impact on the physical development and gene expression, I absolutely believe that reducing the levels of stress hormones developing fetuses are exposed to will go that much farther to producing calmer, better adjusted individuals. It won't change genetics, but it should help.
It may be that a nervous female producing nervous puppies has just as much to do with the influence of her womb environment as her genetics.
Nature vs. nurture, nurture may begin much earlier than previously thought.
And v-girl, I don't support the breeding of any un health tested dogs, regardless of whether they are mixed or not. At 16 months your puppies are not old enough to screen for orthopedic diseases, thryroid problems, etc so you really don't know if your breeding produced healthy animals or not. If the parents weren't screened, then that was just a total crapshoot with all 3 breeds in the mix having a high incidence of hip dysplasia. Honestly I'll be surprised if they are all fine. And to add the dad's temperament problems on top of that...The problem is, with an iffy history, you don't know whether his problems are genetic, or environmental. You just don't know. Dogs of his size are capable of killing an adult human. It's just not worth the risk. Even if they bite and it's not fatal to the human, the dog is still likely to pay with it's own life. Before anything else, health and temperament are the two most important things.
Also, I wouldn't expect a 16 month old puppy to show protective behaviors. They are immature, their personalities are still developing, and many do not show protective, aggressive, prey driven, etc. behaviors until after they mature, which can take over 2 years. There is a very good reason the American Temperament Test Society will NOT test dogs under 18 months of age, and that is simply because they are still babies.
That being said, I do admire you for being willing to take back any of the puppies you brought into the world. There is something to say about that. Thank you.