Saruman's economic infrastructure unexplained?

[Kuruharan]

But hardly the only part.

Agreed.

I think, though, the picture that emerges of the Misty Mountain orcs is that they were less well fed than those from Mordor, for example. In The Hobbit they are referred to as being always hungry which I think it is safe to say indicates that vittles were chronically short. This being so, I think it likely that if things were particularly lean they would bop a few unpopular orcs on the noggin and put meat back on the menu. (I'm sorry, I just couldn't resist.)

In Mordor, even a low ranking orc was referred to as well fed or at least in comparison with Sam. Although, considering how much Sam had to eat perhaps even a mountain orc would look well fed in comparison.

while the movie it looks like the orcs fear it competely, they probaly do in the book, but not as much.

Huh? If you mean in the books the orcs are portrayed as being rational creatures who were to some extent obedient to the Balrog and not a horde of irrational but heavily armed cockroaches then I'd agree completely.

However, this does not mean that the numbers of orcs in Moria were that great. The army that destroyed Balin's dwarves could have been drawn back to Dol Guldur in the intervening time (where the food was probably better).