Yes, you can make your dog's meals ahead of time and store it in the fridge for 3-4 days or in the freezer for up to two months.  Pre-portioning meals in sealed plastic Tupperware is great for easy storage and serving. You can then bring the food to room temperature and/or microwave it.  The oil can be added beforehand if you are storing the food in the refrigerator. If you are freezing the meals, the oil needs to be added fresh right before serving.