Hi all - I have some new packages that I installed about 2 weeks ago. Earlier this week, I witnessed bees coming in with pollen on their legs, but dying on the top of the hive. I live in SW Colorado and thought at first it must be the chilly weather (35-40 at night), but today, I witnessed the bees coming in with pollen on their legs, landing and then shortly thereafter on their backs and dying....I REALLY need to figure out the cause of this before I loose all my bees....thoughts please!