The ostrich is a flightless bird with many unique attributes, including three stomachs. They also possess an unusually long intestine, which requires a total of thirty-six hours to digest their food correctly. The three stomachs all serve different tasks. The glandular stomach assumes the role of the absent gall bladder, and it empties into a muscular stomach, which is called "ventriculus."
The ventriculus is the place where all of the stones and pebbles they ingest help assist in the breakdown process of digestion. From this point, food is then forwarded to the small intestine. The ostrich has a very complex digestive system.
Yes, it is true that ostriches have three stomachs. Ostriches are omnivores which means they eat both plants and animals. Ostriches feed more on plants than they feed on animals. The complex nature of their digestive system and their complexity in terms of size is the reason why ostriches have three stomachs. Ostriches are toothless birds; they can't grind whatever they eat with their mouths.
However, when they eat their foods, they will also need to eat sands and pebbles. Both materials are going inside their stomachs to perform the function of their missing teeth. The stones will help them grind the food particles so that they can digest it very easily. It is important to know that for every food ingested; it will take them about 36 hours for them to digest it. The nature of their stomachs is the reason why they can eat different kinds of things which other animals cannot eat.