I had experimented with pulling pups at different times and found a lot depends on the female. I swear, I believe moms can talk to their pups from the day they are born and the pups understand. For me, the higher the percentage, the earlier to pull. I would pull at 12 days for high contents and 15 - 17 days at any other percent. My pups were never returned to their mother. Once I brought them in the house, that was it. I had a really bad experience in returning pups. The mother literally bit her way through a 9 gauge fence, went through a window in the garage to get in the house with the puppies when I brought them back in. Since then, no mother ever sees me taking her pups and she doesn't see them again. I've had no experience with remorse or sorrow in the mothers. They will look around for one day and then it is business as usual. We fast them for 1 day to help dry up their milk.
I don't know of anyone tht raises pups separately. At that early an age they really need the warmth, smell, etc. of their littermates.
Feeding schedules? Wow That can be complicated.
We pulled pups at the evening feeding for the adults, say around 7:00 PM. We don't even try to feed them for 10 hours. Alot depends on their age when you pull them. Most pups need to be really hungry to accept a strange nipple. Otherwise, they'll balk the difference and feel threathened.
It is easier to start them the younger they are. For ones that already have their eyes open, let them get hungry first. By the time they are 3 weeks, they're eating mushed meat and dog food so they only get bottles to supplement their solid food. Their dietary needs change rapidly from 12 to 20 days so you need to keep up with it to avoid diarrhea, etc. If they were 12 days old, we would be feeding every 4 hours for about 2 days, After that we start increasing the time and ounces so within 5 days they would be on an 8 hour schedule.
Its different when they're oder because they are that much closer to solid food. We wean them off a bottle at 4 weeks. They may still get one in the evening but during the day they get solids and water.
I've know a number of people that have mid-range animals that do not pull them at all. Some of them, the pups are fine and easy to work with and others, the pups are all wired and obviously should have been pulled.
I wanted to add that for me, wolfdogs aren't the only pups that benefit from being separated from mothers. I pull all my little huskies at 4 weeks and bring them in the house. I know people that do this with other Nordic breeds and Livestock Guarding dogs, also.