Agree with nuthatched and Altairsky. The question for whether to ferment is driven by feed form. Use fermentation if you have a whole-grain formulation (goes by various terms.) If the feed is in pellet, mini-pellet, or crumble form, just dampen it, which will help the bits stick together. Example of what I mean by a whole-grain type feed, even though there are "bits" containing vitamins, etc. that aren't whole grains:
View attachment 4141962 (Kalmbach Chickhouse Reserve)
FEEDERS:
For chicks, as in little guys, it works well on those long narrow chick feeders with the holes for their heads. Alas, it doesn't work well at all with gravity feeders, at least not for me.
As they reach 6-7 weeks or so, around the time they are fully feathered, they outgrow this type of chick feeder, and things get literally messy. I used heavy ceramic cereal bowls, which did keep the feed in one place, but they would climb into the bowl to eat, bringing along whatever form of litter you use.
Once mine turned 18 weeks or so and had some real size on them, I started using an elevated dog feeder, a little stand with two cut-outs for metal bowls, easily removed for washing at the end of the day, refilling the next morning. I still find random pine needles, etc. in the bowls, but they're a lot better about keeping their scaly feet on the ground and their beaks in the feed.
FERMENTATION FOR JUST A FEW CHICKENS:
If you do wind up with whole grain-type feed and want to ferment, the methods often vary due to flock size. I only have three pullets (for now, bwah hah hah), and at 20 weeks they generally eat not quite two cups a day. I ferment in two Mason jars. Initially, it does take a few days to get actual fermentation (as opposed to dampened feed) going. Two cups of feed plus de-chlorinated water added periodically through the day will fill a jar. Once that happens, I serve about 1/2 - 2/3 of it in the morning before letting them out of the run, so that they eat most of it, and then MOST of the remainder three hours before dark, leaving about an inch or two of fermented feed in the jar. I add two more cups of new feed, add the water, and give it a good stir. The remaining "old" (not spoiled) feed jump-starts the fermentation, and the jar will be ready to feed in a day and a half. So add new feed Monday evening, feed is ready Wednesday morning. On the day that this jar is fermenting, I feed from the other jar, so it will be nearly empty Tuesday evening, add the feed and water to remaining ferment, stir, and wait until Thursday morning when it's ready. It just keeps rolling along. With a larger flock, it makes more sense to use the multiple buckets that you'll see on Youtube, but this is great for just a few.
IDEAL AMOUNT TO SERVE:
Ha, good luck here! Even before we started yard-ranging them (letting them out of their run into protected areas of the back yard), their appetites were always boom-and-bust. Once they start getting nutrients and calories from non-feed, there's just no telling, and it will alternate between some waste and OMG We're On The Verge Of Death By Starvation days. (My pullets get dramatic on the subject of food.)
I bring in their bowls in the evening when we close up the coop. If there's a significant amount of food left, I keep it until the morning, dumping it out into one of their yard-ranging areas as a little present to find. (We have almost no rodent pressure; thank you, Weirdo Cat.) It does get eaten, presumably by the chickens.
But resign yourself to some waste. It's inevitable. I now have some dry feed available through the day in a gravity feeder. Yes, there's some waste, which I periodically dump into their run litter for them to find.
