I’ve found a few good ideas for things chickens will feed themselves — include the compost area in the chicken pen, the chickens will turn the compost for you, eat fresh veggie scraps, and eat bugs they find.
Put a board or rubber mat down on the ground – let it sit there for a day or two, and a bunch of bugs will move in under it. Flip the board/mat into a new location & the chickens will go after the bugs that have been uncovered.
I also plan to grow a “chicken garden” in their coop — buckwheat, millet, flax, red clover, and forage peas. Hopefully they won’t confuse their garden with our garden. I want to try allowing them to roam in our raised bed garden to eat bugs … but I may end up fencing that off so they don’t eat our veggies!