If you sprout those sunflower seeds you grow it gives them a lot more food and nutrition from them! I have scratch grains I am planning on sprouting just as soon as there is nothing at all to glean from the garden.
There's a used book from back in the mid 70's called Grow It! by Richard W Langer. I've had two copies now because I literally wore the first one out. This has a recipe for chicken feeds, but they still take grains people have to buy. Chickens are resourceful just not completely self sufficient...