I don't know of many breeds with black skin, and beaks. But looking at them in that pic they do look like Silkies.
Spread out their wing and see if their feathers are loose barbs or nice smooth feathers. Usually you can't tell they are Silkies til they are a few weeks old, their feathers might look the same as a non fluffy breed. Our Silkies wing feathers looked similar to the other breeds we had til they started getting older.