Recently I read an article on deworming in the November 2009 issue of American Quarter Horse Journal. It suggests that horse owners have a fecal egg count done on each horse to determine the type of program best suited for that horse. Each horse has a different and unique immune system and should not be given a deworming product just for the sake of deworming. The following article was taken from The Horse website and provides basic information on deworming. See http://www.thehorse.com/pdf/factsheets/deworming/deworming.pdf for more info.
Another bit of info on feeding your horse... http://www.thehorse.com/pdf/factsheets/feeding-easy-keepers/feeding-easy-keepers.pdf.
This is a good article to read on the basics of thrush http://www.thehorse.com/pdf/factsheets/thrush/thrush.pdf.