Well with my aracari, his poop pretty much looks like a pureed version of the fruit he consumed. Especially softer fruits like melons, papaya, banana, blueberries, watermelon. For grapes, I will sometimes see bits of grape skin chunks.
BTW he was avian vet checked and had 3 different poop tests done in July (for parasites, bacterial, protozoa) and all came back clear.
Did you get any fecal tests done?
Some non-avian vets might not be as experienced in what normal toucan poop might look like (it can really wildly vary in color and consistency compared to parrot poop , e.g.)
I did use Avian Enzyme for the first month or so that I've had him, and an avian probiotic supplement, and I think they helped improve his digestion. His poop was 'chunkier' in the beginning before I used them. However, I wouldn't overdo these supplements, due to concerns over increasing assimilation/uptake of iron, etc. Note: these were NOT vitamin/mineral supplements, which of course are NOT recommended for any aracari/toucan.