Philosophy with Young Students-Which Came First?

We are thinking about eggs this time of year. With this activity I blow my kids' minds. :) 

We talk about the life cycle of the chicken. And then I ask my students which came first--the chicken or the egg?

Student:  Well, that's easy the egg.

Me: Who laid the egg?

Student: Oh, then the chicken? 

Me: How did the chicken hatch?

Student *scratches head*-ok so maybe it's not easy.