hood venting outside

You have to get up there and look. If it runs through the attic, go up in the attic. If it runs through the cabinets to the exterior wall (like my hood vent runs), you should be able to follow the duct right to the exterior wall.

Whether it's blocked or not can be checked if you have access to the exterior wall, obviously.

It should vent outside, though. I don't think venting it into the attic space will fly. I wouldn't do that.

Where in Jersey?

I agree with Aggie, nothing should be vented into your attic - not the steam from a boiling pot of spaghetti or the bathroom shower, which is done all too often (mold & rot). A good tell tale is if you have an outside vent near the stove, if in the wall there should be louvers that open when the fan is on and if in the eves a good sized screened opening.