Embryonic development offers a unique perspective on the function of many biological processes because of embryos' heightened sensitivity to environmental factors. This hands-on lesson investigates the effects of elevated vitamin A on the morphogenesis of chicken embryos. The active form of vitamin A (retinoic acid) is applied to shell-less (ex ovo) cultured chick embryos, which are highly accessible and intrinsically spawn inquiry. The student activities mirror the scientific research process, including review of scientific literature, hypothesis formation, experimental design, interpretation of data, and re-evaluation of the initial hypothesis. This exercise supports instruction on developmental biology, biophysics, animal research, and experimental design and is motivated by a clinically relevant health issue.