Symbolism in Jimmy Corrigan

While reading Jimmy Corrigan, I noticed that Ware used a lot of symbolism throughout the book. The symbols that I found that reoccured the most were the robot, the miniature horse, the red bird, and the peach. I understood most of Ware's use of these symbols but others were more puzzling. When using the robot, I believe Ware was trying to symbolize Jimmy's passive life. He lives as if he isn't human by rarely showing any emotions. Because of this, it is hard to figure out what Jimmy is feeling and thinking in certain situations. The red bird is often shown throughout the book as flying freely, so I believe it symbolizes Jimmy's want to live his own life and escape the suffocating hold of his mother. Though I have an idea of why Ware used these two symbols, I have no idea why he used the peach and miniature horse. They both seemed to appear randomly in several of the panels. Does anyone have any ideas?