I don't have my own pictures at the moment(haven't foreseen that I would need them), but I have found useful pictures on the net. In contrary to CJR, it works for me and everybody I know plus some people on the Internet. I will produce some figures with the reservation, that it only concerns my own birds. I don't claim that it works for all flocks in the world, but try for yourself
1)Number of cockerels hatched with such a pattern(eyebrow)= ZERO(out of plus minus 1000)
2)Number of pullets hatched like the chick on the left= ZERO(out of 1000)
3)Note the difference between the 2 chicks.The one on the left: sharply defined head arrow.On the right: blurred pattern and rusty colour.
Number of cockerels among chicks like the one on the right+ light face= 100 %
4) There are some chicks which hatch with marked eyebrow, but it is short and light(kind of see-through). Number of cockerels among the chicks with such an eyebrow + blurred head stripe + rusty colour of the sides of the head = 100%
5) There are very few chicks that hatch kind of intermediate between this signs. They nearly all turn out to be late blooming cockerels
Here is a flock of Altsteirer chicks
Match between lack of eyebrow and big comb= 100%
Flock of Welsumers
The breeder has not had luck here (only 2 pullets , find them)
There is an ancient Polish breed called Zielononozka Kuropatwiana(Polish Green-Legged Patridge) which is 100 % autosexablehttp://www.feathersite.com/Poultry/CGP/PartridgeFowl/BRKPartrGrLeg.html
Check also this adress:http://www.rennmausnico.de/13.html
and guess what the words 'henne' and 'hahn' mean.
I have to add though, that I bought some light brown leghorns from UK, and the differences between the sexes were much less apparent.
The chicks with the eyebrow a la Elizabeth Taylor are always pullets for me.