I'm a newbie also, but everything I read from the seed companies, is that you can't keep them on starter/grower for life. You have to switch them to either All Flock with separate oyster shell, or Layer Feed.
What is protein content of the starter feed?
What is the protein content of the All Flock feed?
Plenty of people talk about the benefits of feeding more protein, or not feeding too much protein--but that only applies if the protein level is different.