No reputable, registered, breeder would let a pup go at less than 8 weeks except under the most exceptional circumstances.
However, in response to your question, you mention you put him in a box (?) How big is the box? does it have a top? Can he see out?
In my experience, the best toilet training tool is a dog crate. The soft ones with an opening lid are the best. For a BC I would use nothing less than a medium size, and I sleep with the lid open. If the pup cries, I drop my hand into the crate and they usually settle down. They get lonely and insecure. Beauty of this is you do not need to fully wake up but can drift off to sleep again.
If they do not settle down then it may need a walk.
With all the pups we have raised, this system has them sleeping through the night within a couple of days. The rest of the house training program depends entirely on how vigilant you are.
I tell all my students that the best way to toilet train is to use a rolled up newspaper. If your pup has an accident inside, you hold the roll in your hand, lift it up behind your head, and with a flick of the wrist, you repeatedly hit yourself in the back of the head, all the time saying "I was not watching my dog. I was not watching my dog. I was not watching my dog".
Last edited by Nev Allen; 05-01-2013 at 02:34 PM.
Border River Pet Resort