I feed my chickens a 16% calf grower feed, they free range anyway, so they get everything else they need. A friend of mine also does this with her chickens, along with whatever else she feeds them. She decided to give the 16% feed to her quail, and they STOPPED LAYING....for at least 2 weeks after she switched the feed. I don't know if she has changed them back, but they have since started laying again.
I was also feeding my quail 20% flock raiser, and was having terrible trouble with fertility! Not so much fertility as 'hatchability'....every egg I opened was fertile, they just wouldn't hatch. I have switched my birds from 20% flock raiser to 28% game bird starter, and am seeing an improvement on the hatchability. The game bird feed is only about $1.50 more than the flock raiser, so not that big of a difference.
I still feed my babies the flock raiser, as I do with all babies that I hatch, even turkeys, which I have been told they couldn't be raised on protein levels so low. I guess nobody told my 3+ week old turkey baby that is thriving on it! I'll go back to flock raiser for all my birds this winter, since they won't be laying anyway, though I'm thinking of doing something about that as well
My egg production also picked up, I was only getting 6 or 7 eggs from my jumbo browns, I have gotten 10 eggs from 10 hens everyday for a week. I have been feeding the game bird starter for about 2 weeks. Today I got 20 eggs from 22 hens, one of which hasn't started laying yet. The other egg will be in the cage in the a.m. when I go out to feed.