What are the motifs in King of the Wind by Marguerite Henry?

I think animals having personalities is a recurring idea. Sham is a thriving and playful colt, a stoic survivor of hardships, a young stallion fighting for his mate, and a faithful and affectionate companion to Agba. In contrast is the pampered, overfed Hobgoblin, doted on by Titus Twickerham, the know-it-all groom.