How Do Roosters Know When to Crow?, Science

How Do Roosters Decide Who Will Crow? It's a Dominance Thing

Why do roosters make that noise?, Earth

At what age does a rooster begin crowing? - My Pet Chicken

Cock-a-doodle-doo!' What really makes a rooster cry out? - The Washington Post

3 Ways to Stop a Rooster from Crowing - wikiHow

There's a Heifer in Your Tank: Do hens listen when a rooster crows?

sexing chickens — Randy's Chicken Blog

Head rooster always first to crow - NZ Herald

Weird Things You Didn't Know About Chickens, by HF Sylaj, Dead or Alive