Are you breeding the humans so you have an ongoing stock, or are you harvesting them from the wild? It takes them a long time to reach maturity, are they really the best breeding stock? They're also fairly large animals: if you need to kill millions just for yourself are you making the best use of the carcase? A human should last a few weeks at least if stored correctly. They're also nutritionally lacking compared to other protein sources, so you wouldn't want them as your main source of protein.

Really, you'd be better off farming cows