You can transform your yard into a 'Pheasants Forever' food plot, and encourage diverse plantings of fruiting shrubs, weeds, and grains, and mulch areas, or piles of developing compost.  Plots of different food crops, to develop at different times of the year, will all make your flock happy and busy, at least.
My birds roam over about five acres of my property, in a spruce border, mixed pasture with horses, and under fruit trees.  They don't go further from their coop, by choice, and eat lots of goodies except when there's snow on the ground.  They still have free choice oyster shell, and a 20% protein all- flock feed free choice, and it gets eaten!
Mary