I quit any grinding feed at 1 week, although there is usually some residual ground up feed in the feeder that mixes with the unground feed, therefore, giving them a transitional period.
I will also let them on the wire at 1 week.
Starter feed?.........I feed (28-30%) it to them the whole time that I have them, simply because I usually release them at 5 weeks of age. If I keep(breeders, etc.) some, around 8 weeks before I change over.
That's just what I do, others may have a different plan.