Roosters “sing” to mark their territory. Anytime there is enough light that other flocks might be out and about the roosters yells to let them know his own area is taken. That means they do tend to crow as dawn comes. However, they also crow at a full moon, when security lights go on, and periodically throughout the day.
I have heard that the only way to stop a rooster from crowing, at least when he is in the chicken house, is to place the very highest perch close enough to the ceiling that the rooster may stand comfortably but too close for him to stretch out to his full height. As the leader of the flock the rooster will always choose the highest perch, but he can’t crow unless he can stretch out.
The actual term for what roosters do in English is to crow. When they crow, the sound they make is described as “cock-a-doodle-doo.” We say that roosters say “cock-a-doodle-doo” because we can’t really pronounce what they do. In French roosters are said to say “cocorico,” in German “kikeriki,” in Spanish “kikirikiki,” in Italian “chicchirichà ,” and in Indonesian “kikeriku .”