He's on 24/7 turnout with two other horses so while I haven't been riding in a few weeks (due to work, weather) I know he gets exercise. He's been on Tribute Kalm Ultra since last fall along with alfalfa pellets and grass/alfalfa hay but we've been reducing the amount of alfalfa pellets so I don't know if it's too much protein. The only thing that's different this winter is that the past few weeks he's had access to the run-in shed and the BO has been putting pine shavings or straw in there as bedding. Maybe he's allergic?
I'm thinking I should call the vet tomorrow but for now I wonder if any of you have any brilliant ideas.