All the rolls and bags on the lead yak were an addition to this issue. I originally hadn’t thought about them, but in doing this sequence (where the rustlers pick up some additional gear) and the scene at the border patrol (where the guards go through their belongings), I realized they would have a decent amount of stuff on them that they’d travel with, IE camping gear, food, etc. If you go back, you’ll see that the gear isn’t shown in the opening sequence of issue #1. Let’s just say the supply-loaded yak are simply off-panel in that sequence, shall we?
Or, since it is a sci-fi book, we’ll say they’re cloaked.