All colors can be jumbos. The jumbo browns are just big coturnix. The rest of them can be the same way. Some people's birds are not all jumbos and some people's are. Size depends on breeding and hard culling, colors don't change much. All of them are coturnix, and they can all reach the same...
Well they're either Dykes or you were mistaken. What color are their chest feathers? And good luck getting rid of 2 roosters. The only way to get rid of them is to eat them or sell them for someone else to eat.