Jungle Dreams by Graeme Base

Humorous, philosophical story.
The not-so-beautiful warthogs are unable to be part of the beauty contest. They are excluded. Within this group is another excluded character, the runt. He meets a wise wildebeest character whose influence makes the story.
The theme is appreciation of self and others, not inclusion/exclusion although that could be discussed as the book is shared. It is a sophisticated picture book.
The beautuful art and humour make the story worth reading, viewing and sharing with adults and children.
It is about human behaviour, of course . You could lead into this gently with a young child if you wish to delve deeply.