Couple of facts to consider about our Orcs race. This should hint at their society.
Orcs don`t have a "peasant unit", most of their units can gather resources - warriors can chop trees or build forward bases. And their archers are best hunters in-game.
More ever, Orcs don`t mind human or elven flesh, and a huge Dragon is even a better dinner.
Orcs are also great as "recycling" enemy structures they destroy.
And lets not forget that DoF "recylcing economy" also allows collecting gold/wood from corpses/destroyed siege weapons.
This way a huge Orcish army can pretty much sustain itself. To some extent you can view Orcish army on a move, as a resource gathering operation.
And yes - Orcs race is the first choice for aggressive player.