I would be worried the new kits will not get enough milk from mom with kits around that should have been weaned at about 3 weeks and mom removed from them.
My doe is absolutely done with her kits by 4 weeks. She actively pushes them away when they try to feed. We have hutches with nursery boxes attached to the back. The doe kindles and raises her kits to 3 weeks in that hutch.
At 3 weeks, we move momma and kits to a 30×36 cage. Mom stays with them for one week, and then she goes to her own cage. By 4 weeks, she is ready to get away, and starts showing dominant behavior that leads me to believe she would hurt one of them.
The kits grow out in that cage until they start showing signs of puberty, then they are seperated by gender and the males are pulled out, put in another cage to finish growing out. That usually happens about 5 to 6 weeks old. The males start chin rubbing, spraying, and trying to hump the females.
Our nest boxes are lined with a grass and straw mixture of Oat, Wheat, and Barley. We have observed the kits actively eating the hay before the eyes are even open. I had one kit at about 7 days old mistake my finger for a bit of straw. They have teeth at that age, and were already eating the bedding.
By the time they are 2 weeks old, they are venturing out of the nest box, and following mom to her feeder. By the time they are 3 weeks old, they are fully eating what mom eats. Then I wait for her to tell me she is done before I take her away from them.
So far, all her litters have been weaned around 3 weeks.