At first glance Chickens vs. Beetles isn't a fair fight, well turns out you're right. The chickens seem to win every time and it's a good thing too because Japanese beetles can do some terrible damage. If you have grape vines and you see your leaves ripped up like the picture below, guess what, you have a beetle problem.
Now the solution is simple, all you need is a few hungry chickens, a bucket, and a good arm for shaking your grape vines. If you can't or don't want to place your chickens directly underneath your vines, place a bucket underneath the vine and then shake. Most of your beetles will fall into your bucket, you can physically remove any hangers-on. Once you captured enough of the beetles, bring them over to your chickens and watch the feeding frenzy begin and end. Once a few chickens catch on, it's over quick. That dish was full of beetles and in the time I put it down and snapped the picture, well you see what is left!
This method of beetle control keeps your chickens bellies full of free high protein food, eliminates the use of any harsh chemicals on your grape vines, and gets you more delicious grapes come harvest time. Looks like a win, win, win to me!