Why are turacos sometimes classified separately from Cuculiformes?

While turacos were historically classified as a family (Musophagidae) within the order Cuculiformes, most modern ornithologists now place them in their own distinct order, Musophagiformes.1

This separation is primarily driven by taxonomic reclassification based on modern biological evidence. Unlike the members of the order Cuculiformes, which typically possess zygodactyl feet (where two toes face forward and two face backward), turacos have a unique foot structure in which the outer toe is reversible. This anatomical difference, along with other evolutionary and biological distinctions, has led the scientific community to treat them as a separate group rather than as part of the cuckoo order.12