Really check out the ingredients; grew up on a farm and we used it for our milking cows teets when they got sore or for the horses when they got chaffed from being ridden to long; think its eucalyptus oil, so not sure if buns can handle that and why are your buns licking this?
I would try to fix what is giving him sore hocks. But I use the bag balm on the rabbits. One of my fav thigns for animals.