I discovered the method I used in sexing Buckeye chicks after observing a couple hundred of them that I hatched about 3 years ago. The tail normally grows in faster on the pullets, and the cockerels do not catch up with their tails until about 2 months of age. The biggest difference I see though is that the SHAPE of the wing at about a week is distinctly different. I don't try to count rows of feathers, because just looking at the chicks standing in the brooder, I can see the difference. I can't change anything about how many I get, but it does help if I need to cull some extra cockerels while they are still small and haven't expended much feed.
I would say I am darn close to 100% using this method of sexing.
But I will add that there are those breeds like Welsummers that should be auto-sexing breeds. BUT I have had some sneaky cockerels hatch out with some of the features you should see in the pullets and have fooled me. That is a breed though that you can't use this feather sexing method that I use on the Buckeyes. Some breeds both sexes feather out the same way at the same rate, and you then have to look for alternate ways of telling the difference. Those breeds with large single combs and large wattles, the males normally start showing red with larger of these features fairly early on, like around 2-3 weeks. But with most things, there are exceptions to this too. Sometimes a male will be a submissive or subordinate to others who are more dominant and/or aggressive, so those more subordinate ones may have surpressed maleness and continue to look more hen-like until they hit breeding season. However, I have never seen this with my Buckeyes, only other breeds that show more aggression.
