Information regarding separating puppies from their mothers, generally, only talks about at what age is it appropriate to remove a youngling from its dam.
There isn't much information about whether pups need to be parted from their mamas for behavioral reasons or not.
Will behavioral issues occur in dogs that don't leave their mothers?
In most animals, that live social with each other (like cats and dogs) the nature added a built-in-health-system.
One part of this is, that individuals that are relatives should not have children together. (Children that get the same genetic material from mom and dad have a very high risk for illnesses).
In most cases this incest will be avoided by chasing the children off, when they are old enough to live alone. This behavior is nature-given (innate) to the parents and could not be trained off (as far as I know). In some cases the nature only wants to chase away the male children, in others both (male and female children).
Under these circumstances it could cause a lots of stress and aggression to the old dog and its child, if they need to stay close together.
