I have been sexing my chicks by watching feather growth between two and 10 days. (you have to watch them carefully over this time) The ones that grow tails feathers first (at just a few days old) seem to be pullets. I then ring them, as they whole batch tends to grow to look the same after a few days/weeks and I would lose them. The cockerels seem to grow their tail feathers a little later. There is a definite difference between the two. I have so far hatched two lots of Lavender Araucana cockerel with three hens, a cuckoo Maran, a Copper Black Maran and a Lavender Araucana hybrid. I seem to have been 80% successful with the sexing, which isn't bad at all. Obviously I have to change the rings to larger ones as their legs grow.
I would love to know what colour eggs any of you have had from such crosses. I have been told that the Copper Black Maran X Lavander Aracauna should produce "green" egg layers, and the other crosses I have should be blue egg layers. I can't wait to find out. They are PoL now, but being cold here in the UK I don't think I will see any eggs now until the Spring.