I came home one day to find my ameracauna hen sitting on the top of my 6' privacy fence...since the neighbors I shared the fence with are fine with my chickens unless they end up in their yard (in which case, they will catch them and give them away--hey, at least I was forewarned), I clipped both hens that afternoon, and have always kept any chickens I have clipped at all times thereafter, just to be safe. I check them every few weeks. The only difference in their lives before the trim and after the trim is that they can't get on top of the fence, and potentially given away to who knows what kind of situation.... They still jump and flap around. They still forage and pick. They still get up onto the 2 1/2 foot high perch in their coop. They still happily chase my dogs (tiny chihuahua's) around the yard.
I have kept and raised parrots for years, and for parrots, wing clipping not only keeps them safely in the home, and not winging away into the sunset the first time a door is accidentally opened, it also makes a HUGE difference in tameness. since my chickens are ALWAYS trimmed, I'm not sure how it might apply with chickens--probably doesn't make a diff like it does with parrots, but it would be interesting to see if anyone had experienced this.
One thing I'd recommend is to trim the feathers on BOTH wings...this will give the bird more control if it does make short flights. If you clip only one wing, the bird will wobble when it tries to fly when it's startled. This makes it easier to catch if it is fleeing a predator, as it will move a lot slower. There are also implications that it can cause one wing to develop differently than the other when you clip only one wing, and it can cause some problems in the wings and back on the bird.
A second recommendation is to check closely for 'blood feathers' before you cut into the wing. Feathers grow in alive, wrapped in a keratin sheath and filled with blood. When the feather 'dies' the sheath flakes off, leaving a fully formed feather. If you cut into a blood feather, the bird can actually potentially bleed out, as they have a difficult time clotting. Now, I've never heard of that happening, but it is certainly messy, and very painful for the bird. Just spread out the wing and check all the feathers to make sure they're fully formed, normal feathers, and the bird will be fine.
Another thing to keep in mind is, if there are blood feathers, you can trim around them, but leave the feathers on either side of the blood feather long to protect it. When it has grown out, trim all three.