She also does not completely molt as smaller hornbill species do. She molts in steps so that she is still able to fly. The clutch consist of two eggs and is incubated by the female for a month. The young remain in the nest for three months and are then fed by the parents for an additional nine months. The young remain with the family unit until they reach sexual maturity, after about three years.
Most hornbills are monogamous.
In species such as the African ground hornbill, cooperative breeding has developed in which some individuals, usually males, although sexually mature, do not breed but help a dominant pair to rear their young. The Masai believe that the African ground hornbill should never be killed because it will bring bad luck. If one lands on the roof of a house, the occupants must move at once or they believe death will ensue. Many tribes in Africa believe that the African ground hornbill is a rain prophet. The Koffirs, of South Africa, took this theory one step further.