I guess if you limit the time the chickens have around your garden and don't let them necessarily freerange in it they will eat bugs and some of the leaves. Mine love the new little sprouts so when I am getting planting started I do not allow them in the garden area. They are happy to purouse through the rest of the yard munching on greens and bugs. Then I shepherd them back to their run or to their coops. Their coops are moveable so I do move them around so they always have fresh ground to scratch but if I leave it too long they do denude the area under the coop. So I guess it is in how you manage your flock and the amount of "free ranging" you allow is the answer to your question.
Caroline
Caroline