Of course there is a chicken!
The egg is full of chicken DNA which would strongly suggest it came from the chicken
you deny exists...
The egg had to come from somewhere, just like the chicken right? Which leads me to speculate thus;
The chicken evolved from a reptilian form (It is widely held that most if not all birds were reptiles in the time of the dinosaurs) Reptiles being egg layers too are thought to have evolved from sea-creatures who were originally simple celled organisims. So tracing it back also leads me to vote for the chicken.
Who are these Adam and Eve you speak of ?..............j/k