Caleb, is it? Do you have a 12 gauge shotgun at your house? Next time your parents go into town for shopping, have them stop by a gun store and buy some rubber shotgun loads. There are a number of people on these threads that would make fun of trying to discourage a major predator with rubber loads, but I've shot both bears and bobcats with the rubber shot, which is very hard plastic the size of marbles, and just as hard, and they never returned once I got a direct hit.
It's far better than trying to kill the predator and just wounding it. Then it can be supremely dangerous. The only drawback is you need to be within 50 yards for the shot to reach its target. If the lion does get bolder and comes in close to the pen, you should have it loaded and ready.
Tony, I'm sure the small predators you do have will be challenge enough without your suffering regret you don't have anything bigger to deal with. It seems once you have chickens, the entire population of meat eating wildlife thinks you're running a meat market.