Yes mailmen and mail woman here carry pepper spray with them and most of them do carry pepper spray in every state and county.
The mailmen or mail carriers use pepper spray for defense if someone attacks them or tries to attack them or if animals such as dogs try to attack them.
However the pepper spray is not always effective at saving them.
There was a mail lady shot and killed by a person who got angry at her for not delivering his mail to him because of dangerous dogs.
So the pepper spray is not always gonna save them.
I wish that the mailmen or mail carriers could carry guns with them but they are not allowed too.