The chicken beacuse God made things in alphabetical order... hohohohohoho

i didn't check it, i only tell you what i think and maybe or indeed is not correct but the evolution is a slow process then maybe the first egg wasn't like it is now and the first chicken wasn't like it is now, and the evolution is a process is not a discrete function. i don't think is possible to know the answer . now , after have written this i have found a theory that tell that first was the chicken because during the life an animal cannot change its dna than the first chicken was born from an egg of another bird , this is a theory that i red on wikipedia

In the truest sense of the word none of them is born. When a chicken lays an egg , some baby chicks are hatched not born;)

Chickens get born, eggs don't. ;)