I watched that video and kept thinking how rough those machines are on the babies, and the way the sexers tossed the babies into the chutes looked rough. Yikes! I think I'm hatching all of my own from now on. lol
I tried feather sexing mine when they arrived from the hatchery a few weeks ago. I didn't mark males from females, but I did count them, which couldn't possibly be accurate, because an order of 25 chicks straight run with only 7 cockerels would take a miracle. lol
At two and a half weeks, my cochin boys are already starting to develop combs, but the silkies will be much harder to sex and will easily take a couple more months or longer before I'll be able to tell for sure. And yes, sexing barred rocks from day old is way easier than most breeds, but that's more coloring than anything.