This takes a few days,especially if you have a lot of hens, but it works. Split into two groups, select group where egg is being eaten, split that, then again till you find the culprit - then leave her on her own with only hard eggs of whatever variety. Take note of when she lays and remove her eggs immediately. It does take a bit of effort putting barriers between them and places for them to have shelter, but it finds the right one. I doubt if you'd get much meat off her if she is a laying hen so I wouldn't bother eating her.