Watch for unfastened stools that may point out difficulty with digestion. Gradually increase the ratio of recent to old over every week or two if properly tolerated. Then increase to 75/25 per week, and then a couple of extra days and you may give 100 percent of the new food plan if all goes well. However, some pets have extra delicate digestion than others, and if there are any indicators that the model new meals just isn’t being properly tolerated , you need to decrease the ratio of latest to old meals.