Yes, chickens peck at the ground and each other for other reasons. They never peck at each other from boredom..... The #1 cause, that they will peck at each other, in an extensive manner, is a protein deficiency. (Light pecking is not what I am talking about).
Look, I realize that you have extensive experience with chickens. But you are wrong about them only eating to meet energy requirements. Chickens are very selective about what they eat, and although energy is their top goal, they will most certainly eat selectively to meet other needs. Chickens are very well noted for doing so.....
If you are concerned about experience, I have more than 20 years, and a BA in animal science. I have specialized in poultry nutrition for more than 15 years of that time.