Yesterday I was watching the activity in my full-size hive apiary, there were lots of foragers on almost every hive bringing in the bright orange Creosote Bush pollen, inspired by our recent rains. Then I noticed that the weakest hive (was about six medium frames of bees + 2 with brood, in their lowest box), had zero activity at its entrance. I went in to investigate, they had sealed brood on two combs, both sides of each with some open brood adjacent (the larvae had not begun crawling out of their cells in search of food - perhaps too chilled). There were absolutely no adult bees in the hive. No recently emerged bees, no robbers, just no bees at all. This is the first time I've ever seen this. I put the two frames of brood in an adjacent hive (hoping they could be rescued), just above their own brood nest. Most of the hives are on the verge of booming, with queens laying rapidly expanding brood nests. There were still lots of honey in the frames, I plan to watch and see if this gets robbed.