I would definitely say the white is a rooster. I really would like to see a pic of the blacks face. Close up on the beak so I could see any possibility of a comb starting. My black hen is at the beginning of this posting next to a rooster if that helps at all. This is my 4month old black black hen.
Still kind of hard to tell. I have 2 chicks that I got at 4 weeks of age and now they are 12 weeks and only about the last week I have been pretty certain they were pullets. Yours doesn't seem to have as much fluff to it as mine do. But their feathers come up really close to their nostrils.
Lol caught my little cuckoo silkie trying to breed a jersey giant pullet this morning. I got him with the black silkie and 2 jg pullets so he thinks they are his ladies. Can you imagine giant silkies lol!
I think that's what I love about my silkies. They always look so silly. I have a hen that I swear she dunks her whole head in the water cause her hair on top of her head is always wet. They are so cooky and silly.
I know silkies are hard to tell at young age... but I am thinking this little cuckoo chick is a cockerel. I have another chick the same age and I see quite a few differences. Then again the cuckoos are very different.