Boost them with brood from another hive if you can.
Scott, I gave them a frame of brood today. I have them on medium frames in a deep nuc. I added a deep frame of brood some capped and some open. This population is really small. I don't know how well they are going to be able to warm the brood. We got a pretty good cold snap on the way. I closed up the SBB and reduced the entrance to a 3/8" hole. Should I add a 75W trouble light under the hive stand to help them keep the brood warm?