Don't let them be free, they get too many problems if left to roam. One of the reasons they are so clean is because they are up off the ground in cages where the poop falls through. No contamination problems or parasits. They don't look sad to me, they look very cute and well cared for, I see they have pellets and hay and are kept safe from predators. You can give them toys if you want, they will play with them.
Are these pets or food?
Are these pets or food?