Hi Kathy J,
In regards to The Honest Kitchen I asked myself the same question in regards to digestibility of the plant matter. I asked the company if they had done any type of digestibility studies and they have not. I specifically asked if they ever did anything as simple as visually inspect “output” and they said they had not.
You can find more information on the THK thread. I hydrated the food, identified and counted the various food elements (sweet potato, cabbage etc) then fed the meal to my dog and evaluated output. I didn’t find the pumpkin pieces and assume it was digested. The sweet potato looked the same coming out as going in. The apple was partially digested and the cabbage and celery pieces had minimal change to them. I then repeated the experiment but cooked the diet before feeding and few identifiable pieces were found.
