Sorry. I could only get one set of horns to parent to the head.  Unless someone else knows of a solution to parent more than one prop to a body part, it seems like you will only be able to parent one set and then have to manipulate the others into place and just leave them unparented while you render.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi