I have a RIR roo who is 18 weeks and has yet to crow. He is definitely a roo, supposed to be a pullet but I understand sexing is usually 95% at best. He is with four RIR pullets the same age. I have three month old d'uccles already crowing but nothing from the RIR. Do they mature slower? Just curious. Also, he has not yet exhibited a mean bone in his body - so far so good!