I know of a single DO in the entire province of Ontario that practices here. and he is a citizen of the country. Canada is in a tight spot right now because they don't even have enough residency slots for their own graduates. It doesn't get easier once you're an attending either -- neurosurgeons and highly specialized practitioners cannot find jobs in areas you'd want to live in, despite demand being high. It's one of the drawbacks of it's highly centralized healthcare system.
edit: just one source of many,
http://news.nationalpost.com/health...ncies-and-full-time-positions?__lsa=c546-4ae7
Use google to find out more!