Generally with silkies it is very hard to tell the sex. I've had supposed males before that laid eggs. The only true way is to sex them. Even then it is hard to tell imho. Have you ever sexed a chicken before? If you haven't then I would just let nature take it's tole and see what comes out of it. By the looks of these birds I'd say they are fairly young. I would wait a few months a see which ones crow and which ones lay.
Thanks
Magnum
The top one is a cockeral while the next 2 are non bearded pullets. Normally the cockeral will have a much wider comb and exhibit are larger set of wattles in comparison to the pullets.
I bought six silkies from a guy 2 years ago. He swore up and down that 5 of them were hens. Needless to say about 5 months later I had 4 crowing "hens" and one rooster. Only one of the six ended up being a hen.
I would guess #1 is a roo too, due to his wide comb and longer wattles. The other 2 look like pullets to me so far. It does sometimes take longer on silkies than other breeds to tell their gender.