It depends on how old your roo is and what breed it is. I have one that crowed at four months and the other took two more months to crow. The one that took two months to crow grew spurs first. They are two seperate breeds.
my roo is just starting to get spurs of any sort of size. he had little nubs but he's 1.5 yrs old now and they are growing, maybe 1/2" long now. he's a NH Red. i assume it would vary based upon breed? crowing, however, he's done for a looooooong time.