Nice to see more of Swamp. For animals as well as humans learning can already take place in the womb. And the learning that takes place in there is so "initial" that it imprints/forms on the individual as part of their temperament. That may be one of the reasons why you noticed the pups from mothers that are being worked (correctly as you do) during pregnancy are stronger.
The study of epigentics came from studying humans first. Epigentics control a lot of the subtleties you see running in familes. E.g. stress can change the methylation of DNA in the mother, leading to children more prone to stress, obesity, addiction, ADHD, etc.
I think they mean if the dam is a good solid trainable dog, the likelihood her puppies will be good working dogs goes up. I knew of a Rottie multi V1 rated SCh/IPO 3 bitch who had her BST, FH1 and FH2. She was bred to some amazing males that were carefully selected for their working abilities as well as health and conformation. The pups she produced in each litter were solid amazing working pups.
