what's the largest breed of draft horses? in what country did they originate?
Quite frankly it varies and depends on who you are talking to at any given moment. While it is not 100% sure at this point but the largest draft horse on record in 2008 is a Percheron 19.3hh 2,700 lbs but that could eclisped at any time. Shires are definitely one of the consistently largest breeds. I would not be surprised that somewhere kicking around in Europe is a 3,000 lbs Shire.
the shire horse, originated in england and is the largest horse as well as draft horse and can be anywhere from 16.2hh(smaller than some horses) to over 18hh
Wikipedia lists the largest Shire horse as 3,300 lbs and about 7 ft 2 1/2 in tall
Shire horse, percheron is a normal a good half hand smaller possibly.