When doing well means breaking stuff

So Cain and Logan are both in schutzhund training. Logan will never be good at this, he is more into herding, carting and we are soon going to get his Therapy Dog certification. Cain on the other hand, this is what he was bred for and he is doing really well. He have been tying him to the fence using my leash and working Logan in front of him to get him to bark more. On Wednesday we were doing this when snap! he comes flying off the fence. Yep, he broke the clip on the leash. Luckily I had one of those nifty leashes that have clips on both ends so we tied the broken end to the fence and clipped him to the good end. He went for another bite, making the whole fence shake and another snap! There goes the other end. *sigh* Well I went out and bought a new leash, this time getting a leather one with larger clips. I still told Joel, my helper, that we should maybe switch to the pole where there is a permanent rope with a large horse clip. My new leash was much more expensive and I don't want to keep having to replace them. On the plus side, this means that Cain is getting much stronger, both physically and mentally.