I've done that experiment. I've also read the scientific literature and the feed trials that the broiler industry did with fermented feed.The gains just aren't there.
http://www.doiserbia.nb.rs/img/doi/1450-9156/2012/1450-91561203433U.pdf
Here's a study that does it - there are some gains...
The problem with the fermented food thread is that people are making all these claims about saving money, and then you read through it and it's like "well, by birds only eat 1lb/week each of fermented crumble, but I feed about 5lbs of scraps, 2 quarts of yogurt, and 2lbs of BOSS each day" - it's...