I'm going to try. My attempt at fermenting an organic grain mash was a mess. The mineral part fell to the bottom and they didn't eat it, but they scarfed up the grains. I am trying dry pellets right now, which they don like, so I'm going to try fermenting them too.
I prefer mash over crumble or pellets for fermenting. As chicks get older i start to mix in grains - even just one grain is good. Its a good idea to continue mixing with a formulated feed if you want to be sure they get a balanced diet.
You can keep rhe ferment at a peanut butter consistency and keep it mixed to prevent things from settling at the bottom.