Donkeys sleep specific ways depending on where they are and how they feel. Donkeys need a specific amount of both light and deep sleep, so it is important that they are able to get both each day.
Donkeys can sleep standing up and it is actually the way they sleep the most often. While standing up, however, donkeys are only able to sleep lightly and are not able to enter into a deep sleep. They have to lie down to be able to enter a deeper sleep.
Donkeys like to sleep while lying on their side or on their chests at some point during each day. All donkeys need to reach a deep sleep at some point during the day to keep their bodies functioning properly.
Donkeys sleep with their eyes partially open sometimes, however, donkeys do not usually sleep with their eyes wide open.
Donkeys sleep for varying amount of times throughout each day depending on what is going on. If the donkey is sleeping or napping while standing, it may be for shorter amounts of time but could be up to two and half hours.