needs a decomposition first. first, render out the fats, should be plenty, then debone it, dehydrate and turn the flesh into charcoal, then the bones become fertiliser. oh, and don't forget the blood....
Sounds like a lengthy process but at least. The liquid blood could be burned and purified. Then the rest I leave with you. But yes we could sequester them into one super cell and feed them just a few crumbs per day as they contemplate their demise.