Can a roosters crow change?

[flowerchicks]

My one year old silkie roo has had the most annoying, shrieky crow since he started crowing in January. But in the last week it has gotten deeper and more "manly". I prefer the new crow and I am sure my neighbors do too, but I want to make sure he isn't sick. He isn't acting sick at all. My other silkie cockerel started crowing 2 weeks ago and he has a deep soft crow. I thought maybe the rooster is changing is crow to sound bigger, to compete with the other roo. Does that happen?

 

[dawnchick]

I don't know the answer and have never had silkies, but I have noticed a difference in the sound of the crow sometime after one year of age in mine. I figured it was sort of like puberty vs. true maturing that takes place in the early 20's in people.