I have 2 Japanese bantams and I love them. 1 of mine is 8 week old and she looks like your chicks. The breeder told me that it is a girl. I got her when she is 2 days old for my Jap bantam broody hen.
My Japanese bantam mother hen is still nursing her 8 week old chick who is too big now to nestle under her wing. She is wonderful mother, still find food for her pullet child. A fearsome mother hen too, she got into a fight with the Wyandotte girl for standing too close to her chick.