That sound similar to what Digi suffers from. Extreamly Sensitive Digestive System caused by allergies to red meats, dairy, & sea food (not including fish).

I make Digi home made food as dog kibble is too risky to feed her.
I cook everything in a pressure cooker as it breaks down all the bones of fish & fowl with ease. I cook all sorts of different fish, and typically feed chicken meat, with some turkey meat, & duck organs (raw).
All Meat is blended together
All raw organ is blended together
Egg shell + yoke (I get 1-2 daily from a co-worker) blended together
I cook fresh veggies (different kinds) in water & blend it together

I then fill the smallest containers you can get at the bilk barn. 1 with meat with a tiny scoop of raw organ on top & a spoon full of the eggshell ontop. 1 with veggie. 1 with mushy rice (digi needs extra carbs to keep her weight up).

Digi weighs between 25-30lbs (weight is up & down all the time) & she gets 1 container of meat, 1 container of veggie & 1/2 or 1/3 a container of veggie everyday.

She looks MUCH healthier & doesn't get sick randomly anymore. SHe only gets sick if she gets into something shes allergic too.