Chickens. Do. Not. Have. A. Penis.
http://www.realclearscience.com/blog/2012/06/chicken-reproduction.html
Seriously, you keep acting like it's this really super easy thing, and we must be stupid if we can't figure it out, when all the evidence presented has been:
It has risks to the chick.
There IS NO penis to check for.
The anatomical variations of chicken sex organs have over 18 different configurations, not two.
Even highly trained chick sexers who do this for a living 5 days a week only manage a 95% success rate at BEST and typical success rate is closer to 90% (which is all the maximum the hatcheries will guarantee).
Look, it's great that it works for you, but it would be irresponsible not to point out the facts of the case, that not everyone will have success with this, and there are risks to the chick so someone choosing to attempt it should proceed with caution and educate themselves before attempting it.