Meowy Catkin
Meow!
Was chatting to my Vet earlier and she said that she's starting to be called out to laminitics again.
This.
And I have only ever seen them in horses with a dietary challenge, in my experience inability to deal with carbohydrate volume. What has happened this week is that compared to the last couple of weeks the temperature has shot up and we have also seen the sun. In late autumn that produces a flush of grass sugars, which will cause the leg swelling in some horses.
My vets tell me that October is the peak of laminitis cases, not spring as everyone thinks.
Your boy may just have had a bit too much sugar.
Hope that helps.