I've been feeding my layers fermented whole grains for around 4 weeks now. It started because I got a bag of Layena that they just refused to eat no matter how I starved them. So I finally gave in and threw them some scratch. Earlier in the year I'd read about fermenting feed so I started soaking it and playing with mixes.
Right now they get a mixture of scratch with wheat, oats, and soybean meal fermented in a bucket with a slosh of ACV in there. But there's something up with the unhulled oats, the girls wont eat them and when I looked at one, it was a soggy mess rather than a firm seed like the others are. So no more of those oats are going into the mix.
The birds really are self regulating as to what they eat. When I first added the soybean meal they attacked it. Now they barely touch the soybean. When this batch is used up, I'm going to be feeding the soy separately. They still refuse to eat any type of crumble, even game bird feed or chick starter, which they used to love. They seem healthy and they are laying really well.