
Weaning can/should be started by the end of week 3 going into week 4 depending on how well the puppies are doing. By this age, their teeth should be coming through and for sure, once mum starts to feel them she won't want to be in there for more than comfort suckling, but this sholdn't be happening at 3 weeks only. No two litters are the same however - we had one who was fine with her first, but quite different with her second to the point she couldn't stand them crawling around her head/face when their eyes weren't even open yet. I had to watch her very carefully!! And this was her last litter .......Her first was 5 male puppies so I bred her again and she gave me mainly males again, but at least once nice bitch to keep, along with one of the boys!
For now, although you can start the puppies, teaching them to lap - using warmed goats milk (be careful about how warm!) and holding each individually on your knee to encourage them to lap and doing this 4 times a day (we'd give our puppies a tiny amount of lean raw hamburger - mince - once a day too) most of their nourishment should still be coming from mum. If she doesn't want to be in with them all the time, fair enough but she should be in with them when they shout to be fed. And you should be sleeping in with her and the litter so you are right there to sort out over-night problems. Like what's going on!!
I'd not shut her in with them overnight, but you do need to be there to get up and let her in when the puppies shout to be fed, for a while yet. As you move on to adding a good quality puppy food to the goats milk or water, mixing it into a porridge, her input will become less to the point that my 6 weeks, weaning should be complete with her nowhere in with them. Our weaning was 'relaxed', depending on how each litter was. When we fed the puppes we had mum out of the box and only let her back in to clean up afterwards and check the puppies. Likewise when she was fed, it was outside the box.