And if you want more reading - particularly if you go the "free choice variety" route, I suggest you start
here, also
here, and
here.
I'd offer more, but my computer blew up late last year (ok, blew up is facetious, "melt down" is far more accurate) and I lost my feed calculator [which I'd been meaning to rebuild anyways] and my entire library of feed studies, and free resources on feeding poultry when the overheating system took out one of my drives, too.
Nor do I have the time right now to rebuild that library.