She's being dominant. Really your other dogs shouldn't be allowed anywhere near where the other dog and her pups are. It's not fair to the new mother. Until the pups are up and moving around she deserves her privacy. In the wild a dog would hide away to have her pups, in domestic situations we should be helping them find that place. I have known mothers to eventually abandon their pups because of other dogs coming into their territory too much when they have new pups. And I'm talking mothers that are super friendly with other dogs any other time.
