Why did my hive die? Pollen question

[Boone]

I had a half box full of bees, and they are dead now. They still had half a hive of honey. A lot of them were dead in the cells. Why do they do that? Any idea how the hive died? Also, I have dry pollen, how do I feed it? Does it need to be wet?

[JD's Bees]

The bees enter the empty cells when forming the winter cluster. The colony shares its food among one another and when they run out will all starve at the same time. If the weather is too cold the colony will not break cluster to reach more food and will starve leaving those bees still head first in the cells.