And just to simplify everything that's been recently posted... you don't NEED to add anything... simply take your grains/crumbles/pellets/whatever, place them in a bowl/bucket, add warm water, stir liberally then cover with a towel in a warm place. Once per day you can stir the mix then set it back aside (<---even THAT isn't REALLY necessary). In 3-4 days, you'll have nicely fermented chicken food. After 2 days, you should be able to smell the ferment when you take off the towel to stir it. Just shovel out what you think your birds can finish in 10-20 minutes, and go watch them turn into velociraptors! If there's food left after they are full, then you know you gave too much and you can cut back next serving. If they clean the bowl/platter/gutter/1/2 PVC pipe, then you could probably give them a little more next time around, and just keep upping the amount till you have just a little left after they're done eating.
I feed my chicks out of glass pie plates in the brooder. They walk in it, and fight for position, essentially getting it all over themselves and tracking it out into the pine chips. I don't mind, because they spend all day scratching in the pine chips and finding little treats to hold them over till I get home from work and give them their afternoon feeding

Then the process starts all over again. It's funny how after they've been fed, if I lower my arm into the brooder they all run for a corner... Before they've been fed, they hover around my hand and arm and make it difficult to lift out the pie plate! or put the filled pie plate back down. They are some silly birds for sure

Hope this helps.