Apparently it is [General] Proctor's opinion that in an open field the whole of Winchester's army would have been wiped out [at the Battle Of The River Raisin]. From the Historical collections, Volume 15 by the Michigan Pioneer and Historical Society.
Monroe, From the Battle-Ground [Frenchtown/River Raisin]
Winchester's whole army was not wiped out but there were at:
"the Close of the Fearful Day saw 600 Americans prisoners of war and 397 dead, the greater number being the defenseless wounded, who were the victims of the Indian war club and tomahawk to which Proctor's cruel treachery had granted full license." [Source]