We bought two black silkies and were told that one was male and one female. Their age is unkown but they are fairly well grown. The one is crowing a lot so I guess he is a male. The one that is to be a female tries to crow. It is smaller and not as colorful.
Silkies are not easy to sex by the novice until the birds are adults. The rooster has shinier neck and saddle feathers and the wattles and comb is more pronounced.
What do you mean with that the smaller one is not as colourful... a black silkie should be black. If you mean the lack of feather iridescence than it could be that that is the hen, although some are slower to mature than others even from the same clutch. The hen should start laying at about 4 month.
The smaller one's feathers are duller and not as shiney as the bigger one. The smaller one was bald when we got it and now its head feathers are filled in. I guess due to stress of being moved around.
Cockerels have a fleshy floppy crest; red when fertile and pale pink when not. The female has a minute crest again red when in lay and pale when not. The thickness of the leg ages the chickens. Of course its only the cockerel which crows at dawn! Hope you dont have neighbours as they wont want to be wakened at 5am on Sundays!