I would transition since one has been on it for six years. And keep in mind it could take several weeks to completely transition over. Try feeding 20% of new food and don’t increase the amount of new food until their stools are normal. Also feeding a little pumpkin purée or giving a probiotic powder or capsule with meals can help with digestion issues. You can also just keep the TOTW as your base food and just mix in different foods just for variety and not actually transition completely off of it. Or serve TOTW for one meal and a different food for another meal.
