Many varieties of bird sing at sunrise and it is the males of the species who sing the loudest and most frequently. No one knows all of the reasons why birds sing, but some of the activity can be explained. Birds sing to attract mates and can accompany the song with specific physical activities. Song is used to mark a bird's territory from intruders and to warn other members of the flock of intruders. It is also used to reestablish communications with the flock after night has passed. Some species do not sing well after they first awake, but improve after a few hours practice. Studies have shown the deaf birds also sing, but their songs are distorted. A rooster is a male bird and crowing is his way of singing.

As someone who used to keep a few chickens in the backyard, I have to disillusion you about roosters crowing at dawn. They will crow anytime of the day or night. They will crow whenever anything startles them - a mouse in the coop, a fox snifffing around the henhouse, a hawk flying overhead, the family dog barking, even the purveyor of food (me) coming into the pen to feed them. My theory is that the sun rising startles them because their memories are so short that they don't remember that it rose yesterday, as well. I have heard them crowing at midnight, at 2 a.m., at 2 p.m., any old time. They might be warning the rest of the flock about a danger (personally, I think this is just anthropomorphization), claiming territory, warning off rivals, even within the same flock, trying to get the hens' attention, who knows, who cares. My point is that roosters crow any old time. We tend to think that they crow at daybreak because : a. they do; b. at daybreak, we are coming out of our own deep sleep and are more likely to be awakened by the sound; and c. we remember things that startle us awake (unlike roosters). Sorry to be so hard on the chickens. I do like chickens, I really do, especially in a nice stir-fry.

I also worked next to a small chicken yard and the roosters crowed at random times all day. It's just the ones that wake you up that you especially notice, and are perhaps annoyed by.

I have three roosters...and they crow at all hours...not just at daybreak......

roosters are samart and so are all chicken! the crow for daybreak.they crow fro teritory and they crow when a predetor is around,just like a watcdog!! i ove my rooster bruce,half bardrock half arcoanna..love my brucy and girls..!

Maybe he gets it caught in the zipper every morning.

When a rooster crows, he’s sending a signal to other roosters that if they trespass, they’re asking for a fight. A rooster will often crow from a vantage point above his territory so he can make others more aware of his presence and so that his songs travel farther. Even though roosters are the most famous crooners of the chicken world, hens aren’t exactly silent. When a hen spots a hawk, she’ll let out a harsh scream to send her chicks into hiding. But if she sees a less-threatening human, she’ll merely cackle.