Yes you are right one of the parents would either have to BE Lutino or the Father could have been split for it to get any WF Lutinos in his clutch. But the only way you could be sure that he carries the gene is if you breed him and you get some, if one of the parents WAS a Lutino (He would automatically get the gene). If his Father was split for Lutino (a female can't be split for Lutino) half of his female offspring would BE Lutino and half of his male offspring would be split for it.
When it comes to sexlinked mutations like Lutino, Pearl, Cinnamon. A hen either is or isn't. She cannot carry a sexlinked gene hidden. It is said of hens "What you see is what you get". Females can however carry Reccesive splits like Whiteface and Pied.
If Spike does have the gene for Lutino you would only need a WF hen to get some WF Lutinos and all of those would be female. With a WF Lutino hen you could get males or females. In order to get males of a sexlinked mutation both parents need to carry the gene.
