In Amers and EEs they can be 5-7 months old before you see saddle feathers....almost as difficult as a silkie...Susans post stated she had EEs and that they were brooder raised =) Thats why I shared...I don't usually fool with feather sexing...I can tell my straight and rose combs by a few weeks anyway...they are my easy babies...LOL And usually they are sold as straight run by 2 weeks old...I cannot keep enough hatched =)I'll have to look into that one.
I know I get good results from feather sexing at hatching and looking at the saddle feathers once they start to feather in. wide well rounded saddle feathers are pullets and tapered saddle feathers are cockrels. but all mine are straight combs.