I have a strong hive exhibiting an odd symptom. In the morning (nights in upper 30-mid 40's) substantial number of foraging bees are chilled and seemingly lifeless on the ground outside the hive. The sun warms these stragglers and they slowly come back to life and return to the hive. At least some are clearly active foragers (half filled pollen baskets), they are not exhibiting dwarf wing symptoms, and on warming can fly and orient themselves to the hive.
The hive has a upper entrance (1 inch hole in a medium) that the bees use in preference to the bottom board. Is it possible that the entrance gets blocked by the cluster and late returning bees don't adjust to using the bottom board.
Are these just "occupy" bees protesting the dominance of the queenly hierarchy by camping out?
Have others had problems with entrance selection, should I block the entrance and force use of the bottom board?