Interested to hear what others have been told/have heard and what you have experienced with your dogs regarding % of protein in food, especially in working breeds that are kept as (active) pets.
One trainer (only works with gun dogs, quite old school) has told us no more than 20% protein in food if they are not working as otherwise they will be hyperactive.
The other trainer we use (works with any dog but does lots of different stuff - agility, scent training, etc) has said minimum 70% protein as it is the carbs that make them hyperactive and he compared lower protein foods to giving sweets to children!
It seems to make no difference whatsoever to our 7 yo golden retriever's energy, although his poo is better on the higher protein food. Not sure yet with our working lab puppy (10 months) but I think we will be sticking with the higher protein food for the time being. Neither of our dogs work, but dh does a lot of training and activities with them, especially the lab, who is insanely clever and makes the GR look like Tim Nice but Dim!