Bisto has always had a bit of a sensitive tummy, but since switching to JWB (no chicken) he's been fine, up till today when we started the switch to adult food from junior. Hmmmmmmm have to keep an eye on this. I have read somewhere that most food allergies in dogs is down to chicken and/or beef!!! Don't quote me on that tho as I can't remember where I read it. I would suggest switching to something with no chicken, and try cutting out their treats as it maybe them.