Chicken can be hard to digest for some dogs so your suspicion may be right ;-) Burns is a working dog food which is quite high in protein - I found Pearl gets an upset tum with anything over 30% which is a shame as I wanted her to have Arden Grange or Applaws
It may be worth contacting some of the named brands to ask for advice and samples (I know Skinners and Chudleys offer this service) to see how you get on once he's a bit better.
It may also be his situation, although he's now in a fantastic home he has gone through a stressful time in his life that may have caused a bit of an imbalance in his gut. Like humans, avoid sugars and keep up with the promax paste.
Hope Barney is fully recoverd soon
Jayne
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