If they're flying and collecting pollen, your good to to go till the weather warms. Maybe give some pollen sub if you've got it.
Probably what happened is they lost some of the cluster for one reason or another (stuck on brood, and starved, mites etc) and chimneyed thru the honey, hopefully the queen's with em. I've got one like that, it's going to be in the mid 60's today and if the wind is gentle, I'm going to peek in to see if they're raising bood.