Have a board or flat surface that you can move the animal on to, and call the nearest emergency veterinarian. An emergency vet may be able to provide you with advice or come out to rescue the injured animal if you are unable to get to them or do not feel comfortable doing so.
Feed your boxer puppy at least twice as much food as he will eat as an adult. Adult boxers typically eat about two cups of food per day, so feed him about four cups per day until he is 6 months old. Refer to the portion guidelines on your puppy food package. Portion your puppy's food into several meals.