Good on you and your wife for having the kids carry their share. I cringe when I see a Mom & Dad packing with their kids, straining under their family loads, while the kids carry a Mickey Mouse pack with a fleece and one carton of soy milk. ;-) Well done! =)
Yes, sometimes (not always) Kessler has the heaviest pack (to slow him down when he's with his sister).
When his mother comes, she can't carry much because of her heart problems and the kids pick up the slack.
Sometimes in the tight slot canyons, the kids will carry most of the stuff because they can fit through easier!