The Last Wild by Piers Torday

Like many children, Kester Jaynes feels powerless, and without much choice in what goes on in his daily life. Kester's situation is unique in that he is mute; he has no voice. He lives in a world where all of the useful animals and plants have died off due to "red eye," a terrible plague. Only "varmints," pigeons, rats, and cockroaches are left alive. Fear of the virus has led to a taboo against touching animals. Food has been replaced by the corrupt Facto corporation with a nutritional slime and the entire human population has been forced to live in cities for their own protection.

Six years ago Kester was kidnapped and brought to live in a home for troubled children, where he is told something is wrong with him. When he starts to hear voices, he thinks he has finally gone crazy. Reality though is even stranger, the voices turn out to belong to a cockroach and pigeons, who help him escape and bring him to a gathering spot of the last surviving animals. These are the last wild; the last living animals and they need Kester's help. Their leader, a large stag, asks Kester to find them a cure. While Kester feels unprepared for the weight of such a task, he promises to try. He even has an idea of where to start, by finding his way back to his veterinarian father. But traveling with animals that society both covets and fears leads to some dangerous situations. As Kester is forced to make more and more decisions, his self-confidence grows. By the end he has found both his father and his voice, but tensions remain as the cure is not wanted by the food controlling Facto corporation.

Overall an imaginative take on a dystopian world that will strike a chord with kids who are starting to make their own choices.