Most complete feeds are made to meet the needs of 'pet' dogs and so may not suit workers. I suppliment with meat, bones veg and table scraps to individuel needs. Mine have plenty of energy are healthy, easily able to tolerate a nights lamping, multiple sprints, or a long run with me, 6 or 7 miles steady paced including at least half free running on beach and burrows. At the end of the day it's about the right balence of carb, protein and fats the source doesn't realy matter as long as it's digestable. The dogs body doesn't care if it's protein comes from a chickens beak or it's breast cooked