
I have never seperated pregnant bitches until labour has started, though have had some that would not stay in whelping box, and insisted staying with their companions until a birth imminent, especially first timers.
I do not allow the other bitches into the room where Mum and newborn litter are, though the others could see through the baby gate, and I had to nip them through living room on lead to take them out for walks.
When my children were young bitches whelped in my bedroom, and Mum and pups stayed there for two weeks.
I then transferred pups in a pen in kitchen with the others.
Mum would allow them gradually to interact.
Eventually I had a bitch who gave the others a hard time if they got too close, until 3 weeks, so from then on I didn't integrate until then.
Have always kept litter in a pen indoors for the sake of the other dogs, especially as some would be elderly.
Outdoors from 4 weeks a pen with doorway at a height for adults, but contain pups.
At 6 weeks, when they could jump the board, all adults and pups mixed.
Some bitches are more protective/possesive of newborn pups, and some bitches would try and take over a litter, both could cause stress or fights.
In the wild a bitch would have her pups in a den, and the rest of the pack would meet them once they had eyes open and could venture out.
I have been told of instances where a bitch has killed another bitches pups, though not in my breed.