Bird hatchlings may be altricial or precocial. Primates are born with intermediate maturation of altricial and precocial species. The span between precocial and altricial species is particularly broad in birds. The chicks of passerines are altricial&colon; blind, featherless, and helpless when hatched from their eggs. Upon hatching the altricial chicks are brooded until the nestling phase. The altricial (naked and helpless) chicks take between 21 and 27 days to fledge. Hatchlings are altricial, naked with their eyes closed. The reptile hatchling is quite the opposite of an altricial bird hatchling. On hatching the chicks are altricial, blind and naked. The chicks are altricial and covered in whitish-down on hatching. Both birds brood and feed the altricial naked chicks and keep the nest clean. They are born altricial, hairless and blind. The chicks are altricial and downy, and are fed by both parents. The opposite developmental strategy is called "altricial", where the young are born or hatched helpless. Chicks are altricial, or helpless at birth.