When we got our first grey, Elliott, we used the Kirkland chicken and rice. He did fine on it, but was super gassy, so we tried the Kirkland lamb and rice, which solved the gas problems. These days we rotate between Nature's Domain salmon and potato (from Costco) and Kirkland lamb and rice, and have recently tried Nature's Domain beef an potato with good results. Chicken doesn't make all hounds gassy, but if you notice a lot of gas, you might want to try a different protein source. We've tried higher end brands, but they actually seem too rich for our two and they end up having soft serve poos.