Philbert, this old timer at the saw shop measured this loop of chain I got from him. I've never seen anything like it before, and want one. . . . But you put a loop of chain on it and it'll tell you the DL count.
I want one too!
We have tried to draw lines on the wall, under loops hung on nails, to to quickly sort our different loops; but with chain stretch, etc., there is a lot of variation, even when you know the pitch and approximate DL count.
Closest things to that that I have seen/used are:
Oregon 556418 Bar And Chain Measuring Tool:
And chain measuring charts like these (Bailey's, Oregon, etc.):
These are each pretty simple, inexpensive, and effective. The chain chart works better for lengths off of a roll, but can still speed things up, compared to counting by 'twos'.