This is my first season and one of my hives is very robust compared to the other--much more bees, just placed second honey super, etc. Queen is healthy, no signs of serious mite infestation, bees foraging normally all looks well--except yesterday I noticed very young bees being hauled out of the hive and left on the ground to die in front of the hive. The numbers are significant but not massive. Today there are a couple hundred dead bees in front of the hive, all young. I would say they were carrying them out at a rate of approx. 1-2 per minute. Theories I have heard is a) hive is so robust the bees are performing population control b) mites--so I am going to treat them today c) insecticide, but why only young bees and otherwise normal behavior? d) lack of water, although massive lake is about 300 yards away or less. I'm clueless and being new it's heartbreaking to watch. I am very grateful for any help you folks can suggest.