They do eat some bugs and greens, but it is their preference for grain that makes them easy to feed. The only catch is their small beaks mean the seeds & grains they consume must be tiny, too. Here Ill share my coveys favorite homemade quail scratch feed recipe that I use as a treat
Homemade Quail Feed Recipes. I found two different recipes you are welcome to try. I think both of these options are probably more to make than buying a bag of feed from your local feed supply store.
Homemade Scratch Feed Recipe for Coturnix Quail | Natural Seed + Grain Feed Blend for Backyard Quail. This EASY natural feed recipe is a blend of 4 grocery store ingredients plus dried meal worms that your Coturnix quail covey will LOVE

This particular example perfectly highlights why Homemade Quail Feed Recipe is so captivating.
https://raisingquail.net/Here's how to build simple, cheap feeders for your coturnix quail that will eliminate most feed waste.
Homemade Quail Feed Recipes. When preparing feed, you need to make grain crumbles in a grinding or pellet machine. Grains and seeds are the base, and you can adjust protein and supplements based on the birds age.

Homemade feed also allows you to cater to the specific nutritional requirements of your quail. Especially if you have different types (layers, breeders, or meat birds). Homemade Quail Feed (How to Make It in 7 Steps).