Get a skarmory found in the route below Blackthorn City (obviously, but make sure it’s female) and then get a MALE Spearow from Route 33 or 42, level it up to 37, (don’t evolve spearow so this is faster, because it’s already slow as it is), then it gets drill peck at 37, and breed the skarmory with the spearow. Then, bam, you have a level one skarmory with drill peck! I know it’s a long and tedious way, but it’s one of the best (if not the best way) to get a Skarmory with Drill Peck. That is the lowest level you can get Drill Peck in any Pokémon available in this game. Sorry, I know it’s tedious.