When you add multi-racial forts (it looked like a valid thing for forts in the upcoming version as of devblog on 12/3/2012), as some players play goblin fortresses, these will get immigrants from other races. Goblins don't need to eat, but the other races do, so if you had a multi-racial goblin fort would we be able to set up farms anyway?
Your civilization won't learn new techniques, so I imagine in your modded case you'll need to import food.
so far as i know, nothing prevents goblins from farming. the only thing is you cannot embark with seeds, by default.
if memory serves, in the current version, abductees tend to starve unless they are made to be [NO_EAT].
i think the major hurdle is that goblins use evil plants (which do not show up ingame still, i believe) or lack tags to use "normal" plants.
as it stands, do hunting and ranching food animals actually provide food to a settlement in worldgen?
oh, as a final note, i recommend removing the no eat and no drink tags from goblins after worldgen, before play, when playing a goblin fort
