Donkeys evolved from the desert. Donkeys living in the U.S.A. are being over fed and fed the wrong foods. Once the neck crest breaks over nothing can be done to repair the neck. Insulin resistance, laminitis and soon death. If you rescue a donkey with this abuse, get a donkey vet fast.
Select https://www.youtube.com/watch?v=lM6DF-3hulM VIDEO DR. AMY MCLEAN, VET.
The donkey must live on a dry pasture or paddock for the majority of their life. If we feed the wrong foods such as alfalfa hay, apples, pears, cookies, oats, breads, or munching all day on grass, brush and trees we will see this in our donkeys neck. Not to mention death. Death comes next as the donkey evolved from the desert, the donkey was created to live on low sugar/protein hay, clean water.
Round bales for the donkey will cause this too! Hay should be measured and controlled as the donkey evolved from the desert.