Bantam houdan gender?

[RachelFromTheBlackLagoon]

I'm going to look at 2 bantam Mottled Houdan chicks this week. They'll be 7 weeks old on the day I go out there. The woman who has them said that she can't see combs or wattles on either yet. At what age would you generally be able to tell the gender of a bantam crested chick?

I asked her to email pictures. However, I don't think I'm able to post pictures with iPhone. If she sends them, could I please email them to somebody to post for me? I'd appreciate it very much!