If you keep on slaughtering the pigs for about twenty times, they will finally transform into Big Boars. These big boars when killed successfully, again twenty times, will in-turn transform into larger boars with deadly fangs. These huge boars with fangs will drop three red orbs each. You can lure one of them to the Brightstone cathedral, and get the Pickaxe. Or let him follow you to the mining/hollow camp after the Doors of Pharros and dig for the axe. The sad part of this process is that you can kill the piglets, which transform into boars which again turn into boars with fangs, only once in the game. The boars will not respawn again. After killing the boars with fangs you need to look for others ways to get more red orbs. You can get these orbs in many other ways too, like buying it from Brotherhood of Blood for five thousand souls each or by killing the fire salamander.