When shipping meat, it's easier if it's all packed in cans than if it's animals walking around. So let's do that with the humans. Surgically remove all the bits you don't really need, like arms, legs, and genitals. We can grow them back once we reach the destination. Then stick in some feeding tubes and catheters, earphones and nice high-definition video display goggles. The humans can wander around in a big video-game environment, with as much space and scenery as they need. With the savings in space and weight, we can cram in more people to get more diversity.