“Every day,” Lightning Dust answered. “Well… this part, and the next part. But when you do it so often, it’s not so bad. Soak, clean, then preen. That’s what my mom used to say. That’s… the last step.” She gestured, and Lucky moved over, standing sideways on the edge of the basin and letting the other pony pull her wing across. “Now you move your head along the wing, looking for feathers that are out of place. Nudge the lower ones back into place under the upper ones. And if one’s broken…” She bit down, and Lucky felt a brief, sharp pain. She jerked her wing back, leaving a bright yellow feather in Lightning’s mouth, with a few dribbles of blood on the shaft. She spat it out, then gestured impatiently back. “Jerk straight out, quick as you can. If it’s broken, your body already wants to get rid of it. The replacement is already trying to push it out. You’re just helping it, and getting rid of a place for gross stuff to grow in the meantime.”