Microgreens, tender greens and flowers are comprised of fiber known as "hemicellulose." This kind of fiber is healthier for a bird's digestive tract than "cellulose" found in mature greens and cruciferous veggies. Cellulose is a tough, insoluble fiber whereas hemicellulose is a tender, soluble fiber that breaks down easily and gently cleanses the digestive tract while infusing vital nutrients. Cellulose is broken down by the "cecum," a blind-ended organ located between the upper and lower intestine found in poultry and other fowl, but not present in parrots. Therefore it is best to avoid the feeding of high-cellulose-containing foods (produce that has the cellulose "woven" into the meat of the food, rather than contained on the outside (skin) where birds can peel the skin off and discard the cellulose).
Read this articleAbout the Cecum (Plural: Ceca)