How do birds make their eggs?

Bird eggs come in all shapes and sizes, from speckled hummingbird eggs smaller than a jellybean to mango-sized emu eggs. But how do birds make them? We asked bird expert Paul Bartell to help us find the answer. Got a question that’s ova-whelming ? Send it to us at BrainsOn.org/contact , and we’ll help crack the case! See omnystudio.com/listener for privacy information.