Wikipedia
Crotophaginae
The Crotophaginae are a small subfamily, within the cuckoo family Cuculidae, of four gregarious bird species occurring in the Americas. They were previously classified as a family Crotophagidae.
The subfamily is notable for the development of cooperative breeding where several females lay eggs in a communal nest. It contains the three anis and the guira cuckoo.
Among the anis, there is considerable variation in nesting habits. One species, The greater ani C. major lays 2 or 3 eggs, while the groove-billed ani C. sulcirostris lays seven. However the smooth-billed ani C. ani will share one nest between several females, with up to 29 eggs in one nest. Incubation takes 15 days for this species.