part of part of preceded_by preceded by embryo stage post-embryonic stage BilaDO:0000003 In birds, the postnatal stage begins when the beak penetrates the shell (i.e., external pipping) (Brown et al. 1997) OGES:000010 OGES:000014 OGES:000024 UBERON:0000092 WBls:0000022 WBls:0000093 WBls:0000103 post-hatching stage postembryonic postembryonic stage stage succeeding embryo, including mature structure uberon life cycle life cycle stage