Not sure if this helps but , I have a have red setter who is active , every time I give him a diet with high carbohydrate he is very manic in his behaviour, may be this is something that you could explore. He also has a sensitive tummy so I have to be careful with what i feed him. He is now on Different dog and even though it is expensive he is doing very well on it. I have had Labradors in the past guide dog puppies and they can be very active. I hope that you can sort this out.