"Canonicity II": Has Yours Changed?

[Inziladun]

Originally Posted by Boromir88

However, the gruesome truth is that what the orcs are more likely to be eating is the slaves themselves. It is well known that they greatly desire the taste of man-flesh. It is very credible that the slaves who are being shipped up from the south are actually what is sustaining the vast hordes of Sauron’s army.

The subject of Orcish cannibalism seems, in the books at least, to be fairly taboo to them.
There is evidence though that they don't stick at eating Men.

When Uglúk bragged about Saruman feeding his orcs with "man's flesh" (which I would think was likely obtained from either willing or unwilling workers or slaves from Dunland).

Grishnákh rejoins with:

It's orc-flesh they eat, I'll warrant.

TTT The Uruk-Hai

Which elicits yells and drawn swords, indicating it was considered an insult.

Later, when Shagrat and Snaga argue about Snaga leaving to bear news, Shagrat says:

'You must go, or I'll eat you.'

ROTK The Tower of Cirith Ungol

Since he'd already threatened Snaga with other things, though, I'm inclined to not take that one seriously.

That said, I don't think they'd hesitate as much as Men would to eat one of their dead, if it was down to that, or starving.