WC Blue or Black Polish?

[izziebean]

Hi! Got some new baby chicks from the local feed store. They were listed as "assorted polish" from Welp Hatchery. I think they are white crested black or blue. I've watched videos of blue polish and they look black when they are first born. Is there a way to tell at week two if they will be blue or black?

Thanks!!

Picture for reference:

 

[Sunshine0235]

Those are black.