+1@osouseless: The question "which came first, the chicken or the egg" is rather misleading as it presupposes an unmodifiable cycle of chicken -> egg -> chicken. Your statement would be correct under the assumption that 1. meiotic variation does not occur and 2. time has nothing to do with change.
Firstly, meiotic variation DOES occur; it is in the formation of the zygote that mutations may be seen. Therefore it is in the progeny that genetic differences may be found. Evolution and change occurs over time.
Secondly, and more importantly, we are seeking to answer a loaded question in that the answer one provides, whether "chicken" or "egg" accepts that one must exist without the other when, in fact, both may simultaneously exist. It also assumes that there is some ideal chicken, under which any other birds which may charactaristically but not identically, appearing birds must be excluded from the set of "chicken." The same follows for eggs. This again rejects the notion of changing genetics through reproduction. But it is ultimately a loaded question and should be recognized as such.
To answer it from a scientific standpoint, it is important that in the transition from chicken TO egg, there may be a genetic change. From the transition (growth) from egg to chicken, there is no change, genetically speaking. Therefore the resulting change, it would have to be egg, from which the "chicken" rises, which comes first, as it is possible the animal which laid the egg does not exactly represent a chicken.
@goodfortuna the MOST important question is HOW they should be EATEN. The ethical and moral answer is that eggs and chicken, prepared and served in any fashion, must be served in the same dish. Because families that get eaten together stay together. And who doesn't like family?