The softer poo is related to the new food, but not necessarily that it will not work-it is too soon to know at this point. He had just become consistently firm with the food he is eating and think back how many days he was on the LID before that happened–his belly has been through a lot in the past month. I would go less and slower–such as a quarter cup to one meal for 2 days, and if he is ok then add quarter cup to 2 meals a day for 2 days, then do another quarter cup increase to one of the meals and so on. Have you added any kefir yet?
On another note, thanks for posting the picture-he has a soft spot in my heart now. My cocker that is grain intolerant has almost the same markings black with a chest that is almost all white and 3 paws that are white. If you decide to try Sentinel, please let me know if it turns his coat dull.
