Biff and I have begun “acclimating” the puppies to spending time in a “crate”. We’ve pulled out the crate we first used for Chev when he was 8 weeks old and lined it with a towel, then put in the most intriguing new dog toy (the “ball bone” with treat rings screwed into the ends) as entertainment and reward. One by one we introduced them each to the space (with the door open and closed) for just a few minutes. One of them grabbed a tennis sock of mine and I let him have that, too. They all did well. A couple of them had to be coaxed out after getting into the chew toy.
I recall getting Chev to fall asleep in my arms at nap and bedtimes and then sliding him into the crate when we first got him at 8 weeks. He handled it easily because he was already asleep and he never stressed out about being in a crate. We made sure there were a couple of safe chew toys in there with him for the times he woke up and wasn’t able to get out right away. We left the crate door open at other times so that he could go in and out of his own safe space.