The chicken or the egg debate

Keira is becoming increasingly interested in where things come from. Especially food. So, at tea, whatever I get served up is immediately traced back to its (usually!) organic beginnings. But, then, the other night when we had chicken omelettes, I should've paused before thinking of making that combination: Keira: What's this? Me: Chicken. Keira: Where do chickens come from? Me: An egg. Keira looked satisfied. Keira, two seconds later... What's this? Me: Egg. Keira: Where do eggs come from? Me: Chickens. Keira: So where do chickens come from? Me: eggs. ...and so we went for a minute or so when Riley, blessedly (for once!) began throwing his leftover food on the floor, signalling the end of his dinnertime, and my spell of being an amateur biologist. Fun Trivia: I read recently that British Scientists in a study have proven conclusively (so they say) that chickens could not have evolved without embryonic development, thus ending the debate, full stop. The egg had to have come first.