You might consider the rules/regs about transporting brain/spinal material across state lines, too. May need to take a method of removing brain or a saw for skull cap.
If you're looking tint with a solid color, the Rit dyes should do the trick. I've never tried it, but you might even be able to 'paint' it on in specific areas too keep the camo pattern. Not sure how much it would bleed though.
I'm one of the visitors from the flatlands, but we ran into one similar to this. Had hiked in 3 miles to get to this spot and found fresh sign and saw a cow & calf. Next day there was a tipi 80 yards from the wallow.