Fly's by the dozen.

Just pondering while I was tying up a dozen.
I buy hooks in 50's or 100's. But everybody tye's by the dozen.
Is this like the hot dog thing where the wieners are sold in 10's and the buns by 8's?
Anybody got any history on this? Why a dozen fly's?


(Just curious)

(Hey! We are limited to 10 images! Something stinkith to high heaven.)
You can't post a dozen fly's!