Blue splash and black make partridge? help with genetics

[verthandi]

I normally hatch just polish eggs and I have those colors figured out. But my splash silkie went broody so I let her sit on 5 eggs. I have her and one other hen in a separate pen from the polish. The roo is a black silkie. So far she has hatched out a white, 1 light and 1 dark gray colored chick......and a partridge chick. Where to heck did the partridge color come from?

 

[georgialee]

There must be something in the roo's background other than just black. Normally a splash x black would result in all solid blue chicks so someone in there has to have a recessive that's showing up.

 

[verthandi]

That was my thought too, but I didn't know if black would cover partridge so it isn't visible. This breeder had had some almost blue partridge chicks at one time, so it is possible that he is not just black.