That's a bit young to be clipping their wings. My girls are 12 weeks and they been free ranging since they were about 4 weeks old. I've never seen them fly more then about a foot off the ground. And the only reason they even do that is to catch up with the rest of the flock.
But if and when you decide to clip their wings I'd wait till their at least 12 weeks or older.
Hope this helps.
It may not be necessary unless they start flying over the fence. My Australorps and BOs are full grown (1 1/2 years) and can barely fly to reach their roost from a hay bale, but the Delawares are younger (6 months) and can fly about 5-6 feet. I am hoping as they get older and fatter they will lose some of their lift. The fence for their run is about 6 feet and I have an occasional escapee.