If you are looking for a pet for your son to ride, you shouldn't get a donkey. In my experience, they are ornery, kick, and DO NOT appreciate anyone on their backs, and these donkeys were trained to be ridden! I would not take any risks around kids, especially young ones. Of course, donkeys are good for protection, but many are needed to protect a flock. Llamas are my preferred option because they provide predator protection, wool, milk if you want to give it a try, and they are very cute and smart. They require little work and will free range in small groups quite well, as long as they are fences in. Many can be trained to come when called, they will eat out of your hand, and they are extremely good at keeping away predators, like coyotes, stray dogs, foxes, etc. they also come in many different color variations and are teeny and adorable as babies! If you did go down the donkey path, I would get Zonkeys, a cross between a zebra and donkey. They are good pets, very beautiful, and look like imaginary animals! When someone comes over they will just stare and ask if they are real. Many people think they are baby zebras and the conversation goes as follows;
Person 1) look! What the HECK is that thing?
Person 2) it's a baby zebra, duh!
Person 1) but it only has stripes on its legs!
Person 2) all baby zebras are born with only stripes on their legs! You are an idiot!
Me) takes on to know one!
Lol! And by the way, baby zebras have stripes everywhere people!