Your pairing (YB het pied x pied breeding) could have resulted in a Het Pied...but all YB pairings to another morph will not result in a YB hatchling.
Het Pied to Pied would result in Pieds or 100% Hets. The YB is "extra" all the hatchlings will not necessarily be YB.
Het Pied to Pied would result in Pieds or 100% Hets. The YB is "extra" all the hatchlings will not necessarily be YB.