Only roosters crow loudly, not hens. Hens never crow and are generally quiet animals, with the exception of announcing the arrival of a freshly hatched egg. This sound is short-lived, never occurs at night, lasts only a few minutes and takes place once every 24 to 36 hours. Some hens are more vocal than others, depending on the breed, but there is no comparing the sound of a cackling hen to dogs that can bark all night long, power tools, lawn mowers, motorcycles, car alarms, trains, and the myriad of other loud noises frequently heard in the neighborhood.
Please note that the 70dB is the potential level of sound energy, but that it would be a rare sound measured very close to the chicken (2ft). The inverse distance law predicts that at ten times the distance (20ft), the sound pressure would drop a tenth, equivalent to a decibel drop of 20dB. That means that for a chicken making a 70dB sound in it’s outdoor enclosure, their neighbor will experience it as 50dB’s- roughly equivalent to a quiet conversation at home. Noise is even further reduced if the chicken makes a sound within their laying coop rather than the outdoor enclosure.
I invite you to watch and listen to my 3 pullets at 9 weeks old- they’re just getting their “big girl” voices, and you can hear a sample of a “bawk” in the video below. Bonus: they look hilarious.