It was mid 50s here today after a bout of cold weather the last week. Around noon my two hives were furious with activity. I have the entrances reduced to the smallest opening at the moment and there was a huge log jam in the front of each hive with bees trying to get in and out. I thought to switch the entrance reducer to the medium opening to help but decided against it. I noticed a fair amount of bees "missing" the entrance and falling to the ground right below. The activity at the entrance at 630pm was much less, however I noticed bees in small groups (also some alone) all around the ground around the hives. I had just placed some weed matting under my hives this year so these clumps of bees were much easier to spot. There was a pile of pollen that the bees had been collecting right below the entrance to the hives where I saw bees "missing" the entrance. Many of these bees seemed very sluggish, barely moving unless I prodded them. I decided to test how they would act in the presence of honey so I dabbed a little around some of the groupings and they eventually made their way over to it. As I looked closer I spotted more of these bees clinging to grass blades nearby. This is more than just the usual dead bee pile I have noticed here and there since I got my hives last Spring. I treated for mites late last summer, in the fall, and again on a warmer day this past January (OAV each time). There has been a candy board on top of the hive since Winter, with one hive consuming 80% and the other 40-50%. I have been monitoring the bottom board all Winter and have noticed only a few mites dropping in Feb and March. There is still solid sugar left in each hive on the candy boards and honey in frames as well. I did an inspection a week and a half ago and saw frames with honey, eggs, and larvae in each hive. I am attaching pictures showing the amount of bees seen at the end of today. I have been reading some information about nosema, tracheal mites and such. Could this just be evidence of bees exhausted from the furious activity earlier in the day? Or is this a sign of something more sinister? I have not checked mite loads yet this season as temps have risen sharply for a day or two and then fall back to normal (20s-30s night, 40s-50 daytime). I figured opening the hive when it was cold was a bad idea. I have attached a link to more photos and videos I took as well.