Cochin 'shouldnt' have an extra toe but Hatcherys don't typically breed show birds either. Silkies have black skin. He doesn't look like anything the really is supposed to have an extra set of toes. If it only has the one, I'd say it was just a deformity.
#1 is a barred rock
#2 looks like maybe a cochin? Fluffy legs...
#3 is a polish, maybe a hour an depending on how that hair comes out...
and no clue on the last two