Grains are basically the same as a lot of seeds. Millet, canary grass seed and oats are all technically grains, and they're the basic elements of a seed mix for small birds. There are other ways you can serve seeds and grains besides putting dry seed in a cup, like soaking or sprouting them. But sprouting doesn't make a whole lot of difference in the nutritional value.
My chart at
http://www.littlefeatheredbuddies.com/i ... seeds1.jpg shows the nutritional content of those seeds plus corn and wheat. The chart at
http://www.einkorn.com/wp-content/uploa ... Matrix.pdf shows a lot more grains too. No two are exactly alike, but they're not all that different either. The calorie content for all of them is in the same general range. They're relatively high in carbohydrates and low in fat. They have a fair amount of protein but the quality of it isn't spectacular. They have a decent amount of B vitamins but several other vitamins are seriously lacking. There's a mix of minerals that looks nice on paper, but the actual bioavailability of it varies.
Feeding a bird a complete diet without using pellets DOES take a lot of work, and a good recipe too. There's more to it than just feeding your bird a variety of healthy foods, because you have to plan for the hard to get nutrients.