I know almost nothing about fermentation, but I remeber seeing a documentary on how they did it in some real poor place just using bags. I have seen a lot of people post about it on here, but I would be afraid of wasting all that time on a bad batch... One other thing I recall is that once you open a bag you either have to use it all or ensure all air is out of the container. Don't remeber why...
Air causes cracked or milled seeds to oxdize; and if it has oils, the oils go rancid. All cracked or milled feed should be used within a short time of that process to get the most from the feed.
Storage of whole grains lasts MUCH longer.
I looked at an experiment done by a BYCer using fermented v not fermented. It was a good experiment with a few flaws-- the next step would be to repeat the experiment with larger numbers of chickens. The inital experiment showed that ferment feeds resulted in healthier birds with better growth.
I think this could be duplicated by adding braggs acv to the water IMO, or adding FastTrack( or other brand) of inteastinal good microbes to the birds via treats.
I have found this true for my own body--I use not yogurt as it has too few, but rather a capsule of 5 billion units. This has kept my GI in far better health. SO I would expect the same for these birds.
Especially birds kept in artificial environments and cannot get to a natural source found by pecking and scratching outside and eating greens and dirt.