Yes, I read about that as well, but was unsure at this point if it is only a one-time behaviour as being the first litter or if I should get rid of her after she weaned her pups.

The first female that had the first litter is a very dominant female, whereas the other two are fairly "shy".

Do you think it would be possible that this is only a one-time thing? Or is it a permanent thing to you knowledge?