White Jersey Giants:
Comb, Face Wattles and Ear-Lobes: Bright red.
Beak: Yellow streaked with horn.
Eyes: Brown to dark brown.
Shanks and Toes: Dark willow, Underpart of feet yellow.
Plumage: Pure white in all sections.
I see no reason for a splash not to have similar coloration of leg color as the White Jersey Giant.
From my understanding, not all Gj will have yellow under there feet because of the hatcheries not maintaining a good standard, but they are still GJ. I have black JG but not all have yellow feet, they were from a hatchery. And I am sure they are not Black Astrop.
I would say that he is a Roo. I have an Australorp that I swore was hen until he was almost 6 months old, then all of sudden he sprouted hackle and saddle feathers and started crowing............... So, there are def. some late bloomers out there.