If you feather sex or try the above method (which I don't recommend) you'll probably be right about 50% of the time 
Feather sexing is generally used on fast maturing, production type breeds like Leghorns, Production Reds, ECT. It doesn't work on slower growing heritage breeds or ornamentals.

Feather sexing is generally used on fast maturing, production type breeds like Leghorns, Production Reds, ECT. It doesn't work on slower growing heritage breeds or ornamentals.