I'm not sure why you would want to clip their wings - are they able to fly out of their enclosure? In which case I would put a top on it or something. Or because you can't catch them? (sad truth - even chickens that can't fly can get away from us if they want to). Or are you thinking if they never LEARN to fly it will be easier? BO's mature into good sized chickens, and once they are grown and laying, they really don't fly very high. I myself wouldn't clip the wings of a 3 week old for any reason - they are growing and developing and learning how to do stuff - important stuff, like get away from something dangerous - so I wouldn't want to interfere with their development that way. They do go through a phase of being very unfriendly - 'skitterish' as you say, but they will get friendly again as they mature and learn that you are the bringer of all good things... I've never heard of clipping the wings of such a youngster, actually.