If correct, then this is called equibole. And such a ball is used not only for donkeys, but also for horses and other artiodactyls. The idea is that food is placed inside the ball and the animals simultaneously try to get food and play with the ball. Moreover, according to the conodiators, they do it with pleasure. In this homemade the master made large holes, apparently under the hay or pieces of vegetables, and the horses do not make a large hole. Oats fall asleep inside. Horses roll the ball, oats spill out through the holes and the horses collect it.
The master printed all the main parts for this ball on a 3D printer. You can download files for printing. True, this icosahedron was developed for other purposes, but also served perfectly as a ball.
Assembly is fairly simple with locks. Then the master pasted the inside with a grid, installed the last pentahedron and cut out the grid in some pentahedrons.
Now it remains only to fill the ball with food and you can begin to train the ass team.