Getting rid of the shakes

It is too much to expect a young dog to cope with both picking-up and beating

Q I have a young English springer. He is the first dog I have trained and we are at the end of our first season beating and picking-up. He’s turbo-charged, which has been a challenge for me as a novice, but his summer work on dummies was going really well. But once we were on live game, things seem to be going awry and he is treating birds with less and less respect the more work I give him. We work on two big shoots and there are a lot of birds. He’s shaking some birds when he picks them and is also becoming more hardmouthed. How do I fix this?