Thank you all for your comments.
Mr. Blue is a sweetheart, maybe that's why he sired a sweetgrass poult.
I just looked up sweetgrass poults (being very new to all this, I had no idea) and found some good pictures on Porter's rare heritage turkey site . Our little guy has the black strip running down its back.
I think it may be a tom. It is very vocal and stands up tall.
A sweetgrass would be a black-winged grey, which surprisingly is not a grey bird. The parents of this poult are narragansetts, which do not carry grey genes, and ironicly are grey birds. I suspect the yellow color is coming from a red gene and the poults is a golden narragansett. In the picture of the possible moms, the lower bird may have a golden tinge, and may be carrying the red gene. The sibling on the left may also have a golden tint.
My suspicion is the dried poult looked more like this...? Although not visible, they also have a dark stripe down the back.
If not, and you really do have a sweetgrass, who are the real parents...