I fed only FF for a couple years... NO savings as my flock already wasn't wasteful... and NO real health benefit.. IMO.
Lots of wasted time feeding a flock as large as mine.
I even tried fermenting my dog food!
My final assessment... simply making a mash creates as much savings as fermenting due to waste. It will help those who really need help... but for an average healthy flock... meh. Many feeds already have probiotics added in... and you don't get something for nothing.. Those little microbes are consuming the sugars in your feed.
Our formulated rations MEET the requirements needed for our birds by law. We somehow think we know more than the nutritionist who specialize in avian diets and work to alter the product they put together for us.
No increased hatch rate, egg size, earlier onset of lay or anything else people claim are all due to FF... Seasonal changes can account for most things and NO bird can go beyond their genetic potential.
My assessment.. FF hogwash.