It really depends on your predator load (both wild and domestic), property perimeter/boundaries and how much time you can spend "babysitting" them at first. IMO young keets are way too easily taken by predators, and after putting pounds and pounds of starter feed into them I want them to survive and earn their keep doing tick, snake and property patrol for me and not just feed the predators for a few nights... so I start letting mine out at 12 weeks when they have a little more grey matter upstairs, and can fend for themselves a lot better. I work with them quite a bit on getting them to come running for treats when I call them with a specific call and also getting them used to being herded around (in the covered pen) without them going totally bonkers and getting all flighty and stupid, long before I start letting them out. (I coop/pen my birds at night in order to keep from losing them to predators, so coming when called and learning the routine of being herded in to coop up each night is crucial for survival out here in the foot hills where I live). This is just what I do, and what works for my flocks. Everyone has their own routine tho.