How Does This Even Happen?

So Rooster and Geoffrey escaped and ran for a couple of hours while I went home to have breakfast.  Rooster came home limping, and later didn't even want to walk, and when he did he had to stop to hold first one foot then the other off the ground.
Well this is why: the slipped footpad.  He actually wore a hole through his pad!
Mom said that after 20 years of Weimaraners (like me!) she had never seen this before.  Me neither.  Some of her Vizsla contacts have seen this, though, and it comes from the wild twists, turns, leaps and landings that these wild dogs do.  Imagine two hours of this punishment!
The remedy was daily treatments of Musher's Secret (stuff made for mushing dogs on snow carrying cargo for miles and miles).  His pad is covered over, but there is still a sensitive spot where the hole was.  It still needs some toughening up.