Where in Mordor is there food?

[Boromir88]

But what do we know of she-orcs? Were there hort-orcs and were they primarily female?~Bethberry

We aren't told much about female orcs, but I think that a good guess would be that they did do a lot of horiculture:

There must have been orc women. But in stories that seldom see the Orcs except as soldiers of armies in the service of evillords we naturally would not learn much about their lives. Not much was known.~The Munby Letter

Bottomline is we really don't know squat, except that their are orc-women and they do have little orc babies.

I really don't think there would be a problem with slave labor here. Yes Orcs were sent to fight, but also we have 'snagas' (or slaves) that were a smaller breed of orcs to do tasks such as slave labor. Also, he had a healthy influx of Men coming into his service. Prisoners were often used as a force of labor, he could use the prisoners the Men had held as well.