Years ago my daughter's 4H group had a field day with what could be at work for my boy, but I am curious with so many people who have a lot better knowledge then I, whatcha think?
This is him three years ago
Than last month
A close up of his back - and a few spots.
Here is his dad
What you can't see from the pics is that he has a very slight roaning on the big spots on his sides. Each of the smaller spots is outlined with darker skin. He was tested and confirmed for homozygous for tobiano. So is there anything else gong on there? (do you see the portrait?)