Just about 4 weeks old.

[matheny00]

Unless the concern is flying over a fence, it's safer when free ranging to give them every advance to escape predators.

I get that completely... We live in the city, so our predator list is much smaller. We will also be outside with them when we let them into the other area that is not the run. We are looking for free fertilizer, mulching, some good old weeding, and bug prevention. So, clipping the wings is being a good neighbor in our case.

 

[BigBlueHen53]

In that case, clip the flight (long) feathers on just one wing whenever they are capable of clearing your fences and getting into trouble. Could be as early as 3 or 4 weeks. You don't want them getting into a neighbor's yard where there is a dog ... or into another neighbor's vegetable garden! A couple months later when they molt into their adult feathers, you'll have to do it again. But often that's all it takes. By the time of the next molt, they'll have forgotten the joys of flying, and their adult bodies will have gotten a bit too heavy for take-off! There should be an article in The Learning Center here on how to do it, it's not hard.