donkey eating bottoms of trees

Question
We have two male donkeys and for the last month or(after losing their companion horse) have started to dig and/or eat at the base of trees. They are fed twice a day on grassy hay and are quite tame. They are real characters and keep us amused, please can you help us with this problem

Answer
Hi Kevin,
            I am sorry about the loss of your horse. It sounds as though your donkeys are not getting enough Minerals. You can go to any tack store and purchase either the loose minerals or the mineral blocks. Since you only have the two, then I would go with the blocks.

This should both help your donkeys and the trees

Lisa.