From a practical point many people use flushers such as labs to hunt grouse and do quite well. Some people even feel they can get more grouse by working quietly without any dog at all. On the other hand pointing dogs add so much to the enjoyment that many pointing dog hunters get to feel that grouse hunting without a pointing dog is not really grouse hunting at all. Maybe a little extreme but it makes a point. As far as the type of pointing dog, most pointing breeds can learn to hunt grouse. There are lines of english setters that have been bred to enhance grouse hunting qualities and I believe their coat gives some protection against the heavy cover common to eastern and midwestern grouse woods. Most pointing dogs, especially from hunting lines, can be trained to retrieve well. Also pointing dogs can be trained to flush birds on command. I trained my shorthair like that and it can be a real advantage to get good footing and then let the dog flush the birds from out of a brushy draw. It does take a little more training to have them flush on command and still be steady on point when they're supposed to.