My opinion and how I do things....I don't give them anything else at that age but the starter/grower, it has everything in the feed they need...
I'm sure somewhere along the line the Avia Charge, and Rooster Booster would be a good thing to supplement once in awhile in their feed or water...I've never used either....
DE I use in my henhouse for the adult chickens...I use some in their feed to help with bugs and worms...I use it in the coop to keep bugs at bay and it helps with the poo smells and keeps the shavings dry.....I sprinkle on the hens and roosters at times to keep bugs off them.....