I fed my adult bully's Jack and Dolly Purina One for 2-1/2 years with no problems, except the tear stain. The tear stain was a problem, but the coats were shiny as can be. The were healthy and the food was allot more inexpensive. I fed them the sensitive system formula, it is salmon based. Now I have five bullies and they are eating the Fromm, Beef Frittata like there is no tomorrow. I go through three 26 pound bags a month. I am going to try them on the Fromm pork and apple sauce formula, since you get more bang for your buck on that one. Heavier bags for less $.
When your friend loves what they are eating, you know they are getting joy from it. Don't feel too bad yet.