How did Travis mark the pigs ears

Travis has taken on the difficult, demanding job of marking the range hog piglets. Marking hogs is dangerous work; the adults don't like anyone touching their piglets, and they're liable to attack. They're wild animals, after all. Fortunately, though, the ever-faithful Old Yeller's on hand to help him out.
Between them, Travis and Papa figure out a way to mark the piglets with the bare minimum of fuss. Travis gets Old Yeller to round up the hogs and herd them in his direction. In the meantime, Travis climbs up a tree, lets down a rope, and scoops up each piglet. Once a piglet's been marked, it's let back down again. It's a pretty efficient method, and it's safe too. But there is one drawback: the hogs are so mad with all the squealing from their piglets that Travis has to spend another hour up in the tree before it's safe to climb back down again.