Is your back yard fenced in? Do the dogs around you come in your yard a lot, or are they just in the surrounding yards? Are these strays? Do you have dogs?
I live in the city, and there are many stray and pet dogs around us. I have a fenced in back yard, and have never clipped wings. I only let the girls out to free range when I'm right there to supervise. I also have 2 dogs of my own, a foster puppy, and my neighbor who shares my yard has a dog. I don't think clipping wings is a good idea at all. It would limit the chickens ability to elude the dog. If you are worried about the chickens ranging over into the neighbors yard, then make sure you stay outside with them when they are out. Also, some breeds are flightier than others and more likely to jump fences. However, out of my more than two dozen birds, I've only ever had a couple that would jump fences, and not very often.