Hockey night in Canada is shown in HD on the NHL Network, when hockey is not on strike. I am sure the NHL Network would rather people watch in on there other than the Canadian station.
Not all of the games are. For instance, I remember multiple times last year CBC showed an east coast game and then a west coast game, but the NHL Network only showed one of them (usually the east coast game) and then it would show NHL on the Fly afterwards.
Usually, the NHL Network will add the Montreal Canadian feed for the early game as CBC Toronto always carries the Leafs game as the early game. The Montreal game on the NHL Network is always in HD whereas the Leafs games on CBC are always in SD.
The CBC and CFTO channels should be carried in HD as they are now broadcast in Canada in the HD format.