It is important that you do not change any food your dog is currently eating to another brand without gradually introducing it. We recommend a gradual transition from your current dog food over to Furlington which should take around 14 days. Please replace some of your current dog food with Furlington Dog food day by day until after 2 weeks your dog is fully transitioned. It is normal during this time, that your dog can have an upset tummy because he needs to get used to something new.