They are so cute and they look to be maybe three weeks old because mine never feathered at 5 or 6 days it was a few weeks before they did...but every breed is different...
I think BBW's will grow faster due to they are meant to be raised for meat. But I could be wrong. I know that when I got broilers years ago, they grew very fast because they where meant to be raised for food. So they grow faster then any other breed. I guess it's the same with the BBWs and BBB's as well.