How does he treat the dog?

The narrator keeps the dog under keen observation for two days. He initially doesn’t feed him food and keeps him only on a water diet. On the third day, Tricki starts showing some changes and begins whimpering. Over time, the narrator realizes that it is boredom and monotony along with overfeeding which has made Tricki bloated and dull. He keeps him with other dogs and gradually Tricki starts playing with them and gets better with time.