Puppies weaning

My Chihuahua puppies are 42 days old and still try to drink milk from their mother. I still have all the babies but will be selling them by the first or second week of January. I started feeding them puppy food liquefied and they love it! but still right...

after they chase after their mother for milk. The mother cried once a few days ago because of the puppies that have their teeth out already... I don't know what to do? should I seperate her?

I usally try to ween my chihuahua pups between 4-5 weeks of age and I don't let them leave until they are 8 weeks. As long as they are eating then yes you need to step in. They will always go to the ninney because it is better. Mom should start nipping at them to keep them away. I would love to see pictures of them.
It is good to get them on a schedule of eating and pottying. I keep my mother away during feeding time but if I am watching them I let them spend as much time together as possiable. They learn so much from there mother.