Small colonys are at a huge disadvantage, and even strong ones can die when the weather changes rapidly from cold to warm, then back again. They begin to raise brood, then are anchored to it trying to maintain temperature etc. They can starve with food inches away, because they won't leave the brood. When they start brooding, they eat up alot of stores in a hurry also. A colony that is in great shape in Feb, is sometimes discovered as a dead out from starvation because again, the weather changed, lots of mouths to feed, no feed coming in.
Finman uses terrarium heaters to keep his tiny nucs from being locked down. It accelerates brood rearing, and he says his colonys grow at triple the rate. I'm giving it a try this spring, as we had snow June first last year. Didn't last long, but it was a shock to my system, so I doubt the bees liked it either.