At about three weeks is the perfect time to start taking puppies out of their cozy spot away from mom and litter mates and doing some one-on-one time with each one for short periods of time.
This is to prepare them for the time when they will be weaned from mom and a bit later separated from the litter mates as they head to their new homes. It also helps to prevent separation anxiety in the future when they are in their new homes and their family has to leave them home alone to go to work or leave the house.
I know, it’s a tough job, but someone has to do it. 😉