Saruman's economic infrastructure unexplained?

[Kuruharan]

if there were any creatures, hunting them was probably dangerous.

Truth be told, that could be said about hunting a lot of things. I'm not sure the orcs would have been put off by that.

The orcs in Moria specifically were probably supplied by Dol Guldur and likely did not rely on eating each other too much, at least not for survival.

I think that for the rest of the orcs in the Misty Mountains cannibalism may have been a more substantial part of the diet.