Pups between 8 to 12 weeks old should be free-fed for at least one month when they are brought to the house. After that, you can give them 3 cups a day daily till they reach the 2-year mark. Puppy Boxers usually require 55 calories for each pound of body weight. Adult Boxers above 2-year-old need only 40 calories for each pound of body weight and you can feed them two times a day. For senior Boxers, you can ask your vet for the specific portion recommendation and divide the meal 2-5 times a day.