My momma dog fed her babies for at over 10 weeks with her last litter. I just let her feed them whenever she wanted. I also started offering them puppy food and they ate they also, but still wanted to nurse off mom every chance they could
Towards the end, she just did it less and less, but I was surprised that she fed them for so long. I think I hurried her first litter and weaned too soon, mother knows best!!