Yeah, feeding different feeds at different stages and then later, juggling different feeds in a mixed flock, waaaaaay too much trouble.
Besides being complicated and having way better things to do, I began feeding Flock Raiser, an all-flock feed, because my layers were refusing to eat their layer ration. The minute I set out the Flock Raiser, they suddenly had voracious appetites. Now I ferment the Flock Raiser, and everyone eats that, from day-old chicks to my aging hens and the rooster. The hens consume oyster shell, which I have in containers screwed to the sides of the run, according to their individual needs.
It's difficult to offer advice about your chicks without knowing what region you are in, Bahamas, Equatorial Africa, Hawaii, Alaska, Australia, Texas? It makes a big difference. Please fill out your profile info so we can gauge our replies.