Puppies can be begin eating mush as early as 4 weeks of age.
So when the puppies reach 4 weeks of age you can begin feeding the puppies some mush.
When the puppies reach 4 weeks of age and begin eating mush you can change the puppies mothers diet back to adult food to also help her decrease milk production.
After 4 weeks of age the puppies can usually begin to get weaned off the mothers milk.
Then as they get older they can start eating dry dog food once the puppies have their teeth fully in.