If they were younger I'd say put momma in there with them for a couple of days and then remove her.
At six weeks I'd just take 'em out of her cage and pop 'em in.
Some will wean more slowly with a large litter, taking out the biggest first and then a couple days later taking out the next five, and then another five.
I tend not to do that as it prevents scuffling among the youngsters.
Are these all from one litter?
If they are from more than one litter I'd take them all out at the same time and pop them into the new pen with a whack of hay or a box to keep them intrigued so there's less "I'm boss, no I'm boss" stuff going on.