My 20 year old donkey, Grady, is acting kind of weird today. I gave him hay for the first time this year, and at first he attacked it. Then he tightened up, curved his neck and laid back his ears. His back was almost straight! Then he started nibbling hay again. He did that about every 20 seconds and each time he ate less and less hay. After a few minutes he walked away and then back a few times. Then he started nibbling hay again. After that I came back up to the house.
He has never done anything like this before, that I have noticed. Does anyone have any idea what this could be? I attached a picture.