I think your lucky they all didn't die, with the cold snap you just had.We have had a great "winter" so far. February was 40 - 55 F. The girls have been flying since January. We just had a 2 day spell last week where the temp went down to 38-40F. The other three packages that I installed the same day are doing fine.
We generally get the fist packages the end of Feb and quite often the temp drops 21F for a week or 2. This is the first time out of 10-15 packages over the last three years that they have just up and died.