I had a dear friend loved appaloosa horses she had one like this. So for her birthday I surprised  her.
I used Rice Krispies for the molded head, the neck was buttercake and white choc ganache layers and made bit thicker than usual to support the head weight.
I put a steel rod through cake board and had my nephew weld a cake slicer that I slid into head and positioned it.
I put white fondant over entire neck then hand painted with black food coloring.