Bunnies out of nest box?

okay, so I just had a litter of 6 lionheads 2 weeks ago. The bunnies have all of their fur and are growing their manes. But 3 of the bunnies keep hopping out of the nest box, at night and in the morning mainly. Once out he just hops around the cage and explores. The problem is when i put them back, some will go to sleep, but there is always one or two that will hop right back out. Is it okay that they are out, or will the mom put them back in? I had a mini lop litter last summer and there was one bunny that would hop out, but when i put him in he would just snuggle down with his siblings and go to sleep. Any info?????