Seems like your post is also completely missing the point: if you want a sustainable economy you will have a sustainable standard of living. That roughly translates to eating grass hoppers once a day at our current population density.
There's very little reason to eat grasshoppers when chicken has roughly the same efficiency at converting food into protein. Especially considering that the necessary infrastructure and marketing already exists for chicken.
Chicken require high quality feed to grow. Grasshoppers just been grass.