I wasn't gonna post but I just can't resist.

From what I've seen in E. TX, hog poop looks a lot like a good firm human poop, but kinda flattened.(not smashed, just not as round) It is usually in the form of pellets clumped together. However, the pellets are of no certain size or shape and are not "always" clumped together.
Also, I've found several hog trails and there is normally "hog poop" all along the trails.

Hope this helps.
Good Luck!