I think its pretty common knowledge that there are large litters and small litters. What I do not think is commonly known is how the size of the littler might affect a puppies development, temperament, and socialization.
Will a puppy coming from a larger litter be aggressive from having to establish itself in the pecking order?
Will a puppy coming from a larger litter, be more aggressive because of competition from more puppies for the food source available when born?
Will a puppy coming from a larger litter resource guard more?
Will a puppy coming from a larger litter be more independent and harder to train?
Will a puppy coming from a larger litter be more or less accepting of other dogs that are not from their initial pack?
Will a puppy coming from a larger litter be more fearful than a puppy from a smaller litter?
I have seen lots of discussion of what people think is the appropriate age for a puppy to be separated, or go to a new home from its mother and litter mates. There are varying opinions on this subject. I am sure each opinion is based on some personal experience and can also be agenda related.
What I think is overlooked, and should be discussed, is how the size of the litter impacts the life of the puppy. I believe this combined with the age the puppy is separated from its litter mates and mother has a lot to do with personality and habits of a dog.