Once you get to this level of biotechnology it may be simpler and more
efficient to engineer pigs to produce meet that tastes just like or
even better than human beings. Frank Herbert, in some of the later
Dune books talked about genetically engineered animals that ate garbage
and produced that best tasting meat ever.
The human drone idea is a fairly decent interim solution until more
effecient, cheaper robtic drones exist. Of course, you could say the
same about any type of human labor.
Dan Hook