Horses have evolved to be the most aesthetically diverse of the many animals. Unlike other animals, we see so many different variations in hair color, skin color, eye color, facial structure, and bodily structure in them. These things make them stand out and, in my opinion, more beautiful than anything else.  With so much variation in appearance, it can be assumed that they are also the most genetically diverse and developed of all farmyard animals, probably because they have been more successful in terms of developing new breeds, inventing news straints, etc.  It's not a matter of opinion that the animal breeds are genetically different, thousands of years of evolution illustrate that. Through simple observation, it is apparent that the arabian steeds have obtained the best genes.