Researchers have found that roosters produces 1 to 2 second crows that can get as loud as 143 decibels. This is equivalent to standing 15 meters away from a jet taking off.
But if that's the case, how do roosters and surrounding chickens tolerate this noise?
Researchers have found that when a rooster’s beak is fully open, as it is when crowing, a quarter of the ear canal completely closes and soft tissue covers 50% of the eardrum. This means roosters aren’t capable of hearing their own crows at full strength. The intensity of a rooster’s crow diminishes greatly with distance, so it probably doesn’t cause significant hearing loss in nearby hens. Interestingly, unlike mammals, birds can quickly regenerate hair cells in the inner ear if they become damaged. Thus, they're likely to recover from hearing loss.