Join Date: May 2011
Location: Edmonton, Alberta, Canada
If it was me, I'd be picking up some temporary hair dye, making a ribbon stencil and painting pink ribbons all over the horse. Most drug stores carry this temporary hair color that comes in a spray can and washes out easily with shampoo (might need a few shampoo/rinse cycles).
If you want to be extra animal safe, use pink kool-aid as dye... it just won't come out as easily. But the temporary hair stain should be safe. When it doubt, get a vegetable-based/vegan dye.