I shot a fallow pricket [spiker] some years ago in similar circumstances, I had passed by the spot on my way out to the end of the piece of ground & was returning about an hour & a half later when I saw the animal, it had clearly become entangled in this short intervening period whilst jumping the fence onto the farm from the surrounding forestry. I considered trying to release it but the chance of a panicked spiker buck lashing out & catching me was very real & any way it was hard to ascertain how much injury it had caused itself already [it subsequently proved to be quite severe]. I decided to back quietly away & waited for the animal to calm itself before shooting from a concealed prone position, the wire was so tightly wound, & had bitten into the joint that it was a real effort to release - I didn't want to remove the lower leg as I had to drag the animal for a distance & wanted to keep it as clean as possible.
One wonders how many animals get hung up on remote fences around large forestry blocks & never found ? Quite a few I would imagine.
Regards, Tyke.