I don't buy Purina scratch because it doesn't tell you what is in it and it looks very yellow to me. Yellow=corn.
Our homemade scratch has whole wheat, whole oats ( the last to be eaten), cracked corn, barley, and sunflower seeds in roughly the same proportions. When I get birdseed on sale, an equal portion of that goes in too.
I is my understanding that the corn in the scratch is what makes it a *hot* energy/carbo feed. By minimizing the corn in the mix during the summer, I don't worry about overfeeding scratch.
The price is going up but then so is the processed feed price. Combining should be starting around here shortly. I plan on stockpiling as soon as possible.