Hi, welcome to BYC!
Funny, the fermented feed thread is actually featured this week on the home page.
Anyways, I ferment my standard formulated ration and offer oyster/egg shell free choice on the side. I use flock raiser with 20% protein for my multi age/gender/species flock. Some people use starter feed or layer. Pick the feed you like best. Pellets or crumble doesn't matter. Whole grains will take longer to ferment than processed stuff, maybe a couple extra days. I agree it's hard to get the mix right on your own for nutrients and may be more trouble then it's worth if you are just starting out. Make sure whatever you do not to drop the protein below 16% for layers. The amino acids that are contained in it is very important to the health of the chicken.
Also, consider sprouting or growing fodder. The 2 are the same but one growing out longer. I have had great success sprouting barley with no mold issues or anything like that. My goats and chickens both go crazy for it! Barley is about 14% protein, so I only do it as a treat, not their main feed. Wheat (12-14%), corn (7-8%), peas (I think 22%)... all kinds of things can be sprouted. Depending on how many birds we are talking, getting the seeds at the feed store is most cost effective usually 50# for $20 or less.
Oh, and if you haven't seen it yet, check out the FF link in my signature line. It has pretty good basic information.
Also note that I feed ONLY FF free choice all day and put it up at night to avoid uninvited guests. Some chickens make take a short time of adjustment after introduction to decide they enjoy FF because they are creatures of habit and it is something new. But before you know it, they will be gobbling it down. I do save at least 10% feeding this way, just on the feed bill. But that doesn't count for increased health and such. What really made me stick with it was how significantly it changed the smell of the poo for brooder chicks!

Although it still smells like chicken poo, it's less foul. (pun intended)
Welcome to the wide world of fermenting and chickens! Hope you enjoy.
Oh, but beware of chicken math... if you save on your feed bill that means you can have more birds, right!!
