There seems to be some debate about this on the internet. I have read posts where people claimed to feed their quail chicken food, cat food, budgie food, millet, Game bird starter, and quail food.
The chap i bought my hatching eggs from says turkey starter which is higher in protein than chicken feed, is ideal for quail especially if you want them to grow well. However the layers pellets i buy for my hens is 16% and the only turkey starter i could find didn’t say. I rang another chap with an extensive quail information website, who makes and sells his own quail food though he had never heard of quail needing more protein than hens and that his quail food had 13% protein.
I found several manufactures that sold a game bird starter (between 25%-28%) but none that did mail order or had stockists closer than a five hour drive, the only one i could get was medicated which is not something i want in a feed.
Eventually i found a feed manufacturer who not only makes quail starter crumbs, but a quail layer pellet as well. Only problem with the starter is that it is only available by the tonne. Which might be a bit much for a backyard flock keeper. Eventually i found an online supplier of the quail layers pellets, so i have a back of that, a giant tub of mealworms (to up the protein a little) and some chicken treats (they sell all kinds of different chicken feeds too).
Now to decided what to hatch next. More quail or more chickens.