Roosters have built-in earplugs.

A rooster’s crow is typically about 80 to 90 decibels but can reach 142 decibels right next to its own head — that’s louder than a chainsaw and enough to risk hearing damage with repeated exposure. You may reasonably think, then, that roosters must regularly go deaf from their own calls, but roosters have evolved a nifty trick to avoid hearing damage. 

When they fully open their beaks to crow, a specially adapted anatomical arrangement automatically closes off a quarter of their ear canal and half of the eardrum. That temporary closure acts like a natural earplug, significantly reducing the sound intensity. As a result, roosters can produce their powerful vocalizations day after day without destroying the sensitive hair cells in their inner ears.