Must I feed my dog anything else in addition to Marengo complete?

No. Marengo dog food is a COMPLETE dog food. This means that all vital nutrients that the dog might need are present in sufficient amounts. The addition of any kind of supplements as well as of other feed components is not necessary. The natural Marengo Fun Biscuits can be offered as a healthy snack.
The Marengo Fun Biscuits harmonise very well with the integral Marengo dog feed.
At Avoid Feeding Mistakes you can find out how one can bring sensible and healthy variations into the feeding diet.