Consider some simple change that has not happened. For example. Your avatar could be upside down, or even sideways. But it isn't. Why not? Because it is a change that hasn't happened. It might happen if you make the change. But so far, there isn't any evidence of it happening.
My avatar is a human creation. It will not change unless I change it.
We can't say the same about evolution. While man can control evolution today (through selective breeding and killing), evolution also happens naturally.
After all, it is the reason we exist.
The point isn't your avatar. That was only an example. The point is change. Some changes happen, some potential changes don't. We don't have any evidence for species to species change in nature. And I am not saying that it couldn't happen. Nature is simply so complex that we don't have enough knowledge of how it works to determine if this kind of change took place.
So far that we factually understand, evolution is guesswork. As far as applying science to the chicken/egg question, we don't have enough knowledge to understand which came first, the chicken or the egg. This is where we need to look in a different science direction. We need to look at the science that proves God exists.
If we can scientifically prove that God exists, then we can look at nature as being something that God set up as it is. This changes, entirely, how we consider the question of what came first.
The scientific proof for the existence of God can be found here:
https://bitcointalksearch.org/topic/m.10718395https://bitcointalksearch.org/topic/m.14047133https://bitcointalk.org/index.php?topic=1662153.40https://bitcointalksearch.org/topic/m.16803380.
This is basic science. It's the desires of people and scientists that has turned their eyes away from considering it. If you search for it, you can find people discussing these things on the Internet, even though they may not be popular.