I read that mama dogs know which puppies are preset to be alpha dogs, and they are sterner with them than with the less dominant pups : Growling at them when they get too pushy and so forth. Humans see this and think the mama dog "hates" that puppy, and so "rescue" it-making sure the alpha puppy never learns good dog manners as it would have if left with the mama dog, and so becoming more likely to be a discipline/behavior problem for their human family.
True.
Litter policy ~should~ be unless the dam is actually devouring a pup, mind your own business.
She knows what she’s doing.