My resuce dog had some pretty hefty insecurities and some hefty destructive behaviours, and I was starting to despair.
One of my patients who raises assitance dogs suggested increasing the amount of protien in his diet, that it was a trick he often used for the assitance dogs (who must be even-keeled!).
I switched my dog's food to one with about 2x the protien and started adding yogurt and hardboiled eggs to his Kong, and occaisional turkey burgers. (oh, boy, did he like the turkey burgers!)
Within about a month or 6 weeks he was off his tranquilizers, which I'd put him on out of sheer desperation, and had no more destructive behaviours.
It was a miracle!
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson