The little one looks like a sizzle. Only a few breeds of chickens have black skin; it is a dominant trait. Sizzles are a breed under development that have all silkie features except for silkie feathering. The silkie feathering is replaced by frizzled feathering. The little sizzle is way to young to sex.
Frizzle is caused by the dominant gene F. If present, it will show.
However, there is a different gene that reduces frizzling: mf. mf is recessive. A homozygous dose acts to reduce the effect FF to approximately the amount displayed by Ff without the modifier. If instead the bird was Ff, the reduction is to approximately ff.
So a bird who is ff mfmf, ff MfMf or ff Mfmf will look similar to one who is Ff mfmf: unfrizzled.
A bird who is FF mfmf will look similar to one who is Ff MfMf or Ff Mfmf: the typical frizzle appearance.
A bird who is FF MfMf or FF Mfmf will have the look of a "curley."