I have a about 50 to 60 bee on the landing board and when a field bee lands they grab her, pock and brood a few seconds then let her pass.
Some times it gets so bad that the entrance is clogged with bees.
There is no fighting and no dead bees.
I have 4 hives and all 4 hives are the same.
Today is the first time that I noticed this behavior.
I have attached a picture.