Perhaps in South Africa you have different products available than we do here in the US? Generally speaking here we have Chick Starter (up to 8 weeks), Grower (can be fed either from day old or starting at 8 weeks, through to laying age). Once they are laying, we switch to layer formula and just feed that. Scratch is sometimes thrown out as a treat. As the previous poster said, the only time we feed multiple types of food is if we have flocks of multiple ages. Even then, when I add my Spring chicks each year, I switch the whole flock to grower and supplement with shell for the layers and that seems to work. Once the new chicks are laying, we go back to layer feed.