My dog has become a problem eater over the past few months and I would appreciate anyone's advice. It started a few months ago when he become less interested in food. We put it down to the fact that he needed his teeth seeing to. He had a dental back in July last year and for a couple of weeks back on his normal food, (dry biscuits with a tin of meat, he won't eat biscuits on their own) his digestion was normal. But suddenly he had a bout of diarrhoea. Had him on bland food for a few days and he was fine then gradually went back to normal routine and it started again. In vet books I've got, his symptoms suggested he had hypermotility and bland food for a few days would be fine. This new routine went on for some time and we came to notice it was the biscuits he had that seemed to be the problem. The brand is Orlando Complete Chicken and he's been on this food for years without any problems. He's tried other complete biscuits and he seems to be intolerant of them too. We put him on a complementary biscuit and his poo instantly went back to normal. By October his appetite was back to normal and he was doing well. That hasn't lasted long as now he seems to have lost interest in food. He will eat tinned meat on it's own but with biscuits he turns his nose up. His teeth are fine, I've checked his poo and he's been wormed because I read worms can potentially start diarrhoea and even loss of appetite. He's a 12 year old ex-racing greyhound. He can't live on bland food and I'm worried he's not getting enough nutrients with being on a complementary diet he's now not eating. Can dogs be fed on just a wet food diet as this he seems to prefer. Are there any particular biscuit brands that suit a dog that is intolerant?
Any advice would be appreciated.