I think the term you're looking for and want to google is "pasture raised". I also did a bunch of research on the subject and here are a few websites I found helpful.
This is the same website but two different pages. Apparantly it's moving but hasn't moved yet so you can still view it.
http://sugarmtnfarmblog.blogspot.com/2007/10/how-much-land-per-pig.html
http://sugarmtnfarmblog.blogspot.com/2005/08/keeping-pig-for-meat.html
And here are three more:
http://www.sare.org/publications/hogs/prod_sys04.htm
http://extension.missouri.edu/publications/DisplayPrinterFriendlyPub.aspx?P=G2360
http://newfarm.rodaleinstitute.org/depts/pig_page/new_farm_archives/ideal_grazers/index.shtml
Good luck!
This is the same website but two different pages. Apparantly it's moving but hasn't moved yet so you can still view it.
http://sugarmtnfarmblog.blogspot.com/2007/10/how-much-land-per-pig.html
http://sugarmtnfarmblog.blogspot.com/2005/08/keeping-pig-for-meat.html
And here are three more:
http://www.sare.org/publications/hogs/prod_sys04.htm
http://extension.missouri.edu/publications/DisplayPrinterFriendlyPub.aspx?P=G2360
http://newfarm.rodaleinstitute.org/depts/pig_page/new_farm_archives/ideal_grazers/index.shtml
Good luck!