All feed is ground up to a coarse flour. Then, if it is locally ground and bagged, is sold "as is". That's mash. It's usually the cheapest.
If it is made into little bits? That's crumbles.
If it is pelletized, that's pellets.
But the shape of the feed doesn't say anything about the content and the intended birds. Some companies make starter, some grower. Some companies combine the two into one product called Starter-Grower. Medicated means it has amprolium added, usually, to help with cocci immunity.
You can leave your chicks on starter all the way to egg laying at 17-20 weeks, if wish. You can feed a combination starter-grower all the way to point of lay. Layer feed is just regular feed, but it is laced with calcium, something only a laying bird can use. It can overload the renal systems of younger, non-laying birds.
What some folks do is this. They find a feed company. A Purina, a Southern States, a Hubbard, a Blue Seal and they simply follow the "program" suggested by their chosen feed company. Such info is often on the back of the bags, and certainly, on the feed company's website. Best regards.
