good morning my friend
So, I get almost 100% of my information from reading..
Sadly I have severe attention issues, but to the myopic degree, not like deficit, but that sorta is a curse. My brain just won't slow the fuck down, one of the reasons I started smoking pot at an early age. I gotta "feed" the brain gerbil in my head, or he starts spinning too much on his hamster-wheel.. Anyways, I love growing plants of all types, i'm also fascinated by homesteading.
If I recall the absolute first time I read about hair as an input for nitrogen was in an ed Rosenthal book, from the early 90s, the old school spiral bound one (a lot of misinformation there, but a good read nonetheless)
Also feather meal and hair are extremely similar in their makeup.
But homesteading sites man.... good shit on those sites..
But I have probably at least 10-12 books on horticulture, houseplants, veggies, roses, etc.
here is a good site, with the information you're curious about.
http://www.motherearthnews.com/organic-gardening/human-hair-fertilizer.aspx