
With our lot, and by the time weaning began, we had the extended whelping box in the kitchen where all the others were. the 8 X 4 box had a door at the end and as the sides were 3 ft (as I recall) mum couldn't get back in. We started by having a chair next to the box and sitting on it, lifting each puppy onto our lap to teach them to lap (oh the English language - lap, lap) the warmed goats milk. And eat a very small round ball of lean mince, once a day. Mum was watching but in no way objecting, or trying to get at their food which, once they could lap and eat up the porridge mix from a round puppy dish on the floor of the box, was how we progressed the litter. She was let in to clean up after they'd all had their fill. That way she saw what was going on and her milk supply gradually dried up as the puppies only needed 'comfort nursing' with her standing up, and wanting out fast when the needle sharp teeth started hurting her.
Mum had her food outside the box and with the rest of our lot, shut out. I can't remember exactly how it all worked, but it did

Oh and by the time the pups were onto solids, my bitches weren't THAT interested in helping them to empty, which wasn't needed. I didn't want her eating their pooh by that time, or licking at their urine. Ewww.