Would love your recommendation for treats!

so I am on a quest to find the right treats for my dog who has a sensitive stomach and is very picky with food. He eats science diet for sensitive stomachs.

I've gotten some treats from the grocery store and he seems to get diarrhea afterwards. So now I'm not sure what to get him.

Hi and welcome.

I'm from UK so commercial brands would be different.
But a professional dog trainer we know uses plain boiled chicken breast cut up intoo small cubes. It's inexpensive and low fat.

The other thing we were told is that the treats should be given only for good behaviour, obeying commands etc.