Here's an update on one of the Broodminder scales I installed January 20, 2017. The hive weight was 76.0 lbs. The weight was pretty consistent until temperatures warmed up for a week - 60° to 70° F from February 17th -23rd.
Jan 20 - 76.0 lbs
Feb 17 - 75.4 lbs (cleansing flights, bees are breaking cluster, more active due to feeding)
Hive weight decreased steadily from Feb 17 to Feb 22
Feb 22 - 71.0 lbs
Feb 23 - 74.0 lbs (pollen coming in, brood developing)
Feb 24 - 74.6 lbs (pollen coming in heavy, brood developing)
Feb 26 - 77.8 lbs (very few bees leaving the hive due to temperatures below 50°F (weight gain due to developing larva?)
Hive weight decreasing steadily from Feb 26th to Mar 1st
Mar 1 - 69.6 lbs (weight loss due to increased feeding in the hive?)
I can see how a colony can starve in the spring. This hive lost 7.2 lbs in the past 3 days.