Haven’t had a Japanese beetle in the yard since the year after I got my chickens!
Mine ignore the adult beetles, but go nuts over the grubs. I used to know someone whose chickens loved eating the adults. He even rigged one of those bag traps so it would funnel beetles into their run. His chickens would sit there staring, waiting for a beetle to fall out so they could grab it!
I had a customer at Jung’s and her chickens LOVED them, so she would bring her bucket of water and pluck them off of nursery stock for us in high summer.
Whatever floats your boat, I guess, LOL!