sexing Brahma & Owlbeard pullets?

I am adding these photos so that some chicken owning friends of mine can see if they are able to sex my brahma & owl beard pullets.  They are 9 weeks old now and i really would like to know.

Kitten update - almost 7 weeks old

They are all doing so well now. I am so proud of Meg, she has been a fantastic mum to them but is getting a bit fed up of feeding them for too long now which is as it should be.
It has been a wonderful experience and i know its gonna be so hard to let three of them go next week.