I don't quite get what you are showing as a way to sex chickens? Are those tail feathers? Wing tips? What breed? I have always sexed by opening the vent gently and feeling for the tiny 'horn' found in males. Heck sometimes it pops right up and voila you have a cockerel. Always be careful however to handle the chicks gently. My neighbor Sue Lee (Vietnam) can go through a whole boatload of newborns in just minutes it seems and she is always right with this method. Its what she taught me as a child. I know of no other, though if I could learn one that doesn't require me to turn the poor little thing over and pop out its butt I'd love to know - plus it would preclude me getting pooped on, too as often happens.
Happy to learn in Tennessee
Mikelyn