Here at Parsons Place Stable, all our puppies are litter box trained. We start the puppies on newspaper around 3wks old, then by 4wks we offer a litter box or area with shavings or pellets, the puppies naturally figure out how to use it. In our whelping rooms the puppies have access to a doggy door, which goes out directly into a litter box. Dogs by natural instinct typically do not wish to eliminate themselves where they sleep, so the puppies go out the door and use the box. In the beginning they are not very good, they may only get it right 50% of the time. But, by the time the puppies are 8wks old, they have got it down almost perfectly!
The main key to litter box training for puppies, is to keep their space very small. There should only be room for thier bed, food dishes and 1 or 2 litter boxes. As they get better their space is allowed to get larger.
We recommend the puppies using a litter box after they go to their new homes. Puppies have no bladder control until after they are 16wks old. They typically need to go out to relieve themselves every hour. (although they may sleep thru the night).
If you are like me....you may not have time to take your new puppy out as often as they need, or you may have to leave home for a longer period of time. This is where the litter box training comes in really handy! If you can set up your puppies home space with a litter box, you will not have to worry as much about if they need to go potty.
I have found no issues with housebreaking after using the litter boxes. We still take our puppies outside to potty as often as we can, this way they still get rewarded for using the bathroom outside.