I have a 5 week old silkie that was making that noise. I knew it was a roo!!! It has a larger comb, but I have read that with silkies you don't know what they are till they start laying or crowing. I have read lots of info and nothing said they could crow at 5 weeks. But that is exactly what he sounded like. Maybe a bit more high pitched. Not sure. My two 8 week old silkies go BOKBOK when I pick them up so I am guessing pullets. I do have an 8 week old roo too though that I got from someone else and his comb is way bigger than the other two. So I am pretty sure on him too. Not as hard to tell as some say or maybe I just got lucky and mine read the books on what silkies are suppose to look like at their age huh? Cinnamon (He/she) is a cutie either way!!!
Marie