I have a Welsummer hen who began growing spurs before she was a year old. She's now five, and they are an inch long because I keep them trimmed. 
I also have a Cuckoo Marans hen who has, not a pair of spurs, but just a single inch-long spur on one leg. I have no idea where the other spur is.
Neither hen has any other secondary male characteristics, and they both lay eggs regularly during the egg season.
I also have a Speckled Sussex hen who crows on occasion. She's also a normal hen in every other respect. She has no spurs, however.
By the way, the flock has two roosters, so none of these hens is vying for the job.