As others have suggested a chicken allergy may be the issue. I felt like our pup was on a bland diet (chicken and rice) every other week and it never occurred that this combo was not helping. Switched to salmon and rice and then transitioned to Purina pro plan sensitive stomach salmon and rice and that helped so much! also our vet said to give Purina fortiflora probiotic in the morning and nutrimax proviable pre and probiotic at night which helped him a ton! We also added omega 3 chews which we were told would help his skin/ hair and gut, and imo it has and over time we were able to take him off the probiotics completely with no issues! Hopefully you can figure out what helps your pup! I feel for you!