Why do a chicken embryo and a cow embryo look very similar even though the adults do not?

A chicken embryo and a cow embryo look similar in early development due to the shared evolutionary ancestry of vertebrates, which means they retain common features during the early stages of growth. Both embryos develop similar structures like the notochord, somites, and pharyngeal arches, reflecting their shared genetic blueprint. As development progresses, species-specific traits emerge, resulting in the distinct forms of adult chickens and cows. This phenomenon illustrates the concept of conservation in embryonic development across different species.