I emailed customer service at Purina asking about the by-products and grain. They should answer me in a day or two. Or I will call them if they don't. I asked them what exactly is in the grain by products and grains. I'll post the reply when I get it. You all got me curious now as to what they put in. All the other feeds, including horse feed have listed corn and soy separately from the grain stuff. If Purina is hiding that fact behind "by products" I want to know.