Close to a chicken a measured sound pressure level of 60 dBSPL is possible. At the ear of a listener far away from the chicken the level must be much less. We got the distance law 1/r for the sound...
When hens are frightened they make a loud cackling sound. In the hen house when a hen lays and egg she announces it to the flock very loudly and can do so for a long time. When the rooster wakes up...