Some dogs have a propensity for a little hard mouth. He may have been whacked by a wing or had a bird peck him. I think the more he retrieves the less the problem will occur. Don't use a shock collar for this problem, you might end up with a dog who won't pick up a bird. I used to use a collar on my GSP's but I found that they do more harm than good. I finally sold mine. Better off with a whistle.
