Was just rereading my notebooks and found reference to some very successful pheasant hunts toting a Hunter Fulton 16. Probably need to find something like that for a rain gun.
Dogs don't always enjoy hunting in nasty weather. I've seen two pointers and a shorthair go down with hypothermia. One of the pointers was a very cold Dec day in North Dakota, but the other pointer and the shorthair were with temps in the 30's. Hunting pheasants, not raining (or at least not any more than some light mist), but the cover was very wet.