There are pros and cons to keeping dog food in either a bag or a container. It really depends on your individual needs and preferences.
Bags of dog food can be more convenient because you don't have to transfer the food into a separate container. They're also often less expensive than buying containers specifically for storing dog food. However, bags can be difficult to seal tightly, which can allow moisture and pests in. Bags also take up more space than containers.
Containers offer better protection from moisture and pests, but they can be more expensive and take up more space than bags. If you choose a container, make sure it has a tight-fitting lid that will keep the food fresh.