I used it on my beard donor area and it worked quite well to reduce any inflammation from ingrown hairs which for me seem to occur at the 2 week mark and lasts for about 2 weeks. Additionally it reduces the itch.
I have a chicken with a prolapsed vent and part of the treatment is to apply witch hazel as it reduces inflammation, shrinks the tissue and reduces pain same as with humans. One has to keep in mind that these types of treatments are based on a very long history of empirical evidence and have stood the test of time as being effective. So I would definitely consider it.