According to Holm & Shilling (1982: 73–74), to feather refers not only to the process of chickens getting feathers but also to the beginning of puberty in humans. Thus, by extension, feather may refer to "facial and body hair, especially of adolescents“ (1982: 74).
Source: Holm and Shilling 1982: 73
Source: Holm and Shilling 1982: 74