I have a dog who has had lots of stomach issues. Yorkies are very prone to pancreatitis and I've seen time and time again a lot of these air dried and freeze dried foods are VERY high in fat and often
cause pancreatitis. Ziwipeak could have definitely done it. It sounds very similar to Jackson's tummy issues and he has pancreatitis and possible IBD.
We have to feed very low fat food. Something to keep in mind with WET/canned food is to always convert the fat % to dry matter basis.
https://www.pawdiet.com/articles/dry...-for-pet-food/ - this is something I wasn't aware of for the longest time. You may see a canned food that says "3% fat" and you're thinking "oh that's low!!" but once it's converted, it's actually 25% fat.
Recommendations for most pancreatitis pups is to keep it under 10% fat ideally. I'm not saying for sure this what your dog has but it sounds very likely.
Did they do bloodwork? Did they do a specCPL? What was the amylase and lipase levels?
I feed my boy Royal Canin PW Moderate Calorie kibble with Weruva Cirque de le Mer canned (tuna based food). I find he does best with fish. When he has a flare we often feed whitefish and potatoes. Chicken and rice doesn't sit well with him personally.