Here is one of the places you can become an expert on Hackle.
My Daughter, Liz wrote it several years ago. It was first published here on FAOL. I do not have my fingers on the location but is is also on our site. Here is the URL for you to read.

http://www.conranch.com/hackle_article.html

Liz is co-owner of Conranch Hackle

Denny