Duckling Identification?

[Chessieowner001]

Does anyone know if the black looking duckling would be a Khaki Campbell or Cayuga or maybe something else? There were other ducklings from my local Tractor Supply store that I thought were Khaki Campbell's that were a lighter brown and I already bought 2 Khaki Campbell's that have adult feathers in and they were a lighter brown color when I bought them.

Also is the grayish colored one a Blue Swedish or something different? I have two Black Swedish that have flight feathers but I'm not sure what this little guy is. Can anyone help me please?