The Purina brand is the most popular brand and the reviews are awful, my cat had diarrhea for a month, had to give him chicken and rice until I learned it was the Purina causing the problem. Same exact thing with my greyhound dog, the foster gave him Purina. Seemed ok for a few days then the same thing happened... For all you know Purina has parasites.... Hope you can try deworming and a natural indoor kibble...🙏🙏