Being very particular about the most important meal of the day.
And since breakfast comes before lunch, we now have verification that the eggs came before the chicken.
Which makes sense, because dinosaurs were laying eggs long before chickens even evolved.*
* Unless you rephrase the chicken/egg conundrum in terms of "Which came first, the chicken or the CHICKEN-egg?" in which case all you have to do is define whether a chicken-egg is an egg that a chicken comes out of OR an egg that comes out of a chicken, because while usually they are one and the same, there had to be at least one generation between dinosaur and chicken where that relevant answer lies.
(I still vote egg.)
(See also Poultriceratops.)