I have a big garden. That's part of the reason I don't free range my chickens, even though the garden has a fence around it.Good luck with that! Good luck to all of us owning chickens and trying to plant much of anything right now.
I save all the feed bits and dust that fall to the bottom of the chickens' bowls, and dump it into a bin. I use that to make their afternoon chickie snack, wetting it down to about peanut butter consistency. I add whatever kitchen scraps I have on hand, a few bit of spinach, and there is never any left at the end of the day. They know what it means when I sing the chickie snack song.