Is there anyway to tell? (Budgies)

[Hatching]

I have a recent clutch of 5 out of a sky blue yellowface1 SF opaline hen and a light green greywing male. All the chicks ended up normal light green(wild type) but is there anyway to tell which of them have the yellowface gene?? By looking at their faces I think it would be impossible to tell seeing as they are wild type greens.

 

[Tony K T]

I would think they would all have the gene,but may not show in many of the future keets.
In N.H.,Tony.

 

[Hatching]

I would think they would all have the gene,but may not show in many of the future keets.
In N.H.,Tony.

then hen was a single factor, only half could carry the yellow face gene. The all have a yellow face because they are wild type which just adds yellow to all the buggies feathers