Here is a link to our video on how to process them. 
. That may help answer some of the questions on that part of them. And yes, we left on ice over night before we packaged them to allow them to rest.
I honestly don't know of very many people that will put them in a tractor other than us. It's a concept that I believe is gaining in popularity due to our videos, but time will tell if it is truly the best option. We have actually been asked to speak at a conference this weekend about it, so we will see what kind of backlash we get on it LOL. Yes, they like to fly (although only about 3' off the ground), so most people keep them in cages, or I have seen a few aviaries or flight pens that people keep them in as another option. Since they are so small, they can escape easily and I have watched them walk through 2x4 welded wire pretty easily, so I wouldn't suggest poultry net fencing.
RE: Why Quail? Well We Just Processed And Packaged ~100 Pasture Raised Quail