Not sure what flocking is, but what works for us is putting the geese in small familes from 6-10 in a spread and have about 10-15 familes in the spread. We use silouette's and have had a lot better success than with Bigfoots. Also we use the final approach blinds and cover them with mud to take any glare off they might have. Also especially late season you must have some sort of movement in the decoys and the more people calling the better. 
I hope this helps, we shoot the majority of our geese after Dec.1 every year.
I hope this helps, we shoot the majority of our geese after Dec.1 every year.
