Anyone that has studied basic biology would answer the egg. This is the one paradox that truly can be answered by science (not math). If you think about it logically. How does Darwin's theory of natural selection occur? One substance or living being wants to do something so in a set period of time it gains the ability to do so. Same logic for the chicken and the egg. Following Darwin's theory, the chicken came from a previous ancestors (possibly the T-Rex). These creatures, whatever they may be, laid eggs, and something slightly different from the original creature emerges. This cycle repeats itself but the one constant in the midst of variables is the egg. Thus the creature, whatever it might be, has laid the egg the will become what we know today as the chicken. Something, besides a chicken, has laid an egg that has mutated to what we consider to be a chicken today. That chicken came from an egg. That egg however did not come from a chicken, it came from some other organism that through evolution, laid an egg that mutated to become a chicken. Thus in the end, it clearly points towards the egg.
