chicks are pretty easy to let out in the yard - make sure there are no dogs/cats, have the cage/pet carrier/cardboard box at the ready, and enjoy. You can make a temporary "play area" with chicken wire if you are super nervouse.
I had chickens for about 6 years in a city back yard with a chain link fence (about 4 feet tall, I think), and I had "heavy" breeds - buffs, astrolorps, barred rocks - and they stayed in the yard 98% of the time. Squirrels caused a panic on two occasions, and the chickens flew over the fence and couldn't figure out how to get back inside. Neighborhood kids retrieved them once for me, leaving me a stern note about properly caring for the chickens, and the other time I retrieved them, easily.
If your chickens know you, and if you have trained them to come to you (make a habit of shaking a treat can and always giving them treats when they hear it, or making a certain call and always offering treats when they respond to it), you should have no problem getting your chickens if they do stray.
Don't leave them out unsupervised!
Caution: flighty breeds, are, well, flighty! bantams and light breed are more likely to fly
I never ever clipped wings, but some people do
have fun!