Not a chance my dog could be made to wear anything, let alone something covering her eyes or ears.
I don't consider muzzle blasts a problem in the field, as I hunt only uplands with my dog and she's very seldom down range when I shoot (if she is, I'm usually too afraid to hit her by accident, so I avoid the shot altogether).
In the field, muzzle blasts dissipate quickly in all directions, sound is absorbed by trees, and hearing damage is minimal (I don't wear hearing protection myself when hunting - never seen a need for it).
If at the range, perhaps gun training the dog, I would keep her well back from the firing line, where the report is still loud, but not to the point of damaging her hearing.
In a duck blind or constantly shooting over the dog is another matter and one for which I have no viable solution at present. I don't do these things but, if you do, you may have an issue.
A much greater risk to your dog's hearing IMHO, and one that gets far too little attention by some, are ear infections. Far more canine hearing loss is a result of ear infections than all other causes combined (my opinion, not backed up with peer reviewed data). Any dog that hunts is at risk. In the uplands, dogs get bits of plant matter and grass seeds in their ears. This organic debris starts to rot when it settles in the warm, moist environment inside your dog's ears. Retrievers of migratory birds get less vegetation in their ears, but they get small amounts of putrid swamp water in their ears. This also starts to ferment in their ears and leads to deafness.
You can get the ear spray at any pet shop, no vet's prescription needed. Your dog's ears should be treated regularly and even more often during hunting season. Use your nose as your guide. If your dog's ears smell anything other than neutral, they need to be treated. No need to get carried away, once a month should be in the right range for most city dogs - once every 3 or 4 days during hunting season.
If your dog is a farm dog, rides in the back or your truck, or is generally an outside dog, you'll need to increase the frequency of routine treatments outside of hunting season - every 2 weeks, for example. Don't get carried away. More is not better. 5 - 10 drops in each ear for each treatment is sufficient. The main ingredient in the spray is alcohol (comes in a squeeze bottle, not actually a spray). What you're trying to do is to kill bacteria that is cultivating in the outer ear near the base of the ear canal. Using too much spray has the potential of creating the moist environment that causes the problem in the first place.
If you're concerned about your dog's hearing, I'd make this a bigger concern than loud noises in the field (again, assuming you're not constantly shooting over the dog).
