we don't start housebreaking puppies for several reasons.

First, most of the time the pups are too young to be housebroken. 

Second, there are three housebreaking systems  used.

1, outdoors

2, newspaper/wee wee pads

3, litter-box

if we started one system  it limits their ability of  fitting into a home that wants to use another system. a pup can't switch in mid-training. once fully trained in one they can switch but it may take some pups 6 months to a year to become fully training to the first.

so it is better to let the new owner choose and start what system that fits their lifestyle