
I would be very pleased with that gain in my own breed.
As they have done so well, I would leave Mum to feed or not feed them as she pleases now that your are offering alternative nourishment. with a small well grown litter like this, who have had Mums best, it isn't unusual for weaning to f9inish early, as they are well ahead and ready for other food.
Once they start to get around more the weight will be run off.