I can't get a print out of the article but There was an article that Horse Illustrated did in the September 2005 issue on Minature horses I remeber that there where some interesting Facts and info in that article if you can get ahold of that Issue I think it would help you greatly!!
I have the link to the Horse illustrated Site so you can order it if you want so here it is
http://www.shopanimalnetwork.com/subcatmfgprod.asp?0=212&1=216&2=-1
if you scroll down to almost the bottom of the page you will find the september 2005 issue it's $8.00
I hope this helps
Sara