Why are some donkeys spotted?

Their not really "spots", they look more like a paint on a donkey. Donkey breeders look for color just like a lot of people prefer color on their horses. If a donkey is not pure, and has horse in them, that would make them a mule. All donkeys have only donkeys in their bloodlines. There is no way a horse is in the bloodlines, because ALL mules are infertile and cannot breed. Every once in a while, you'll see that one in a million miracle, but in reality, it doesnt happen.

Some donkeys just are spotted,same way some dogs and horses are spotted. They could still be a breed,or it could just be their coloring

Just like horses, donkeys can be different colors. It's all about genes. Genes make up how a horse or donkey looks. Just because their spotted doesn't make them "impure". :)

donkey is not a breed it is a species and they are spotted for the same reason some horses are spotted...because people like them that way and bred them to have color.

Its just their coloring, they are still a pure breed =)

Because they're bad hiders.

cuz their all the more lovable