Bumble foot treatment observations

We've all known the problem... Here is my experience and observations after treating half my flock, many of them more than once, for bumblefoot.

I had a flock of 19 chickens - 15 Hyline Browns (AKA Red Sex-Links), and 4 Barred Rocks.
Soon after we moved to the Eastern Shore (of Maryland), I started noticing bumblefoot in my chickens. Two of them had the standard swelled-up foot. The first one was easy, although confusing at first. Pic below:

AND:
[ATTACH...

Bumble foot treatment observations