I've just read through this thread quickly and when I have more time I'm going to look up all the links and such. This is a good thread with good information. I don't know about the fish meal (as it's not something obtainable in my area) or the bone meal.
The grain is my area. I don't have the feed values at hand...but chickens love millet and its a good feed for them, especially the smaller chickens and smaller breeds. Millet is also very cost effective. I got the guys to keep 800 bushels back for me.
Peas and soybeans have a high protein content. But soybeans must be heat treated for the grain to be acceptable for monogastrics. I haven't used either, but many used soybean meal for their sheep for the protein content. Some don't want to use soybeans because it's GMO and that's an individuals choice. If you can find a farmer who would sell peas (if you have a way to crack them) they would be much cheaper to use than store bought.
Screenings is something else you can use, I'm using wheat that's not cleaned and it has a lot of what you'd call "screenings" That won't be high protein but it could fill the spot of a portion of your grain but likely at a lesser cost. We get "docked" for anything that doesn't make the cut when we sell grain. Dockage is small grain seeds and weed seeds. Then they sell it and make money from it.
When we clean our grain for planting after we get a germination test on it...we get our screenings and they're used for feed for our cattle.
I've had an awful time since August when our brand of chick starter was no longer carried because the store shut down. I've tried 2 different brands on two separate bunches of chicks and I've had had vitamin deficiencies show up. (Twisting, beaks, bent toes, leg issues etc) The parents and all the chicks before the switch have been fine.
I'm on my 3rd type of prepared feed now and I think it seems to be holding its own. You can also buy a bag of additive to add to your grain to make sure your chickens are getting a balanced diet. I believe the bag I purchased last year was 1 scoop to 6 of grain. It's quite cost effective. But I didn't continue with it so I don't have any concrete results.