This is an article about gorillas and how, when they first got them brought into captivity, they kept on dying after just weeks or a couple of months until they figured out it was the human omnivorous diet was doing it. But even just as recently as the 90's they were still feeding them completely wrong food -monkey biscuits [which, by the way, were used to raise baby parrots ] Why? Because the food we gave them didn't have the right kind or amount of fiber and was not providing the right kind of good bacteria for their intestines - eerily similar to parrot pellets problems, right? Pellets being dead food without any good bacteria and manufacturers using the same kind of fiber in them they use for humans, which doesn't do diddly squat for parrots [there are studies done with grays on this].
https://www.msn.com/en-us/news/us/somet ... ar-BBJToVR