Steel Tiger...I hate to even ask, but any
possibility of pesticide exposure?
Do they just kind of fall off the landing?
It's possible. People could be feeding their lawns and laying down grub control as well. Spring planting is just starting, so nobody should be spraying their gardens yet.
The bees come out of the hive, fly up, then land on the grass. I don't know if old bees die in the hive and get carried out or if they leave the hive to die.
Another possibility would be that they're bees that were damaged during the ride home when I picked them up.
I'm going to set up my camera and video about 20 minutes of each hive entrance, then go through and see what I can see.