Is it safe to assume that anything safe for chickens to eat is also safe for quail? There's less info on what's safe for quail to eat than chickens. I'm thinking both of table scraps, etc, and of plants that are safe to have in nibbling range.
They love cooked egg (mashed up), clover, alfalfa sprouts, sunflower sprouts, meal worms (any bug they can fit in their little beaks really), silverbeet/Swiss chard, dandelion leaves, and millet as a treat (as its low in protein). Those are the treats we've discovered are their favourites. I'm sure there are more that others have tried.