Pick a food that’s high in calories to keep feeding amounts (and usually costs, too!) down. My 130 pound rott mix only eats about 3.5 cups (less than half of what most foods say he should eat).
The highest calorie foods I can think of off the top of my head are the NutriSource foods. Super Performance is 529 a cup, I think, and others are all in the mid to high 400’s per cup. They are decently priced too . Around here, the 30 pound bags go for about $50-60 for the grain free.
I would find a protein source they’ve never had before and start there when pin-pointing allergies. Bison is becoming a popular choice these days, as are beef and salmon. Finding allergies does suck. I’ve got one that I’ve decided is allergic to pollen after a year a half of having him on every protein and carbohydrate mix I can find.
