Chameleons are all different, but for the most part I would say that they are a bit more irritable when shedding. It may be stressful if it takes a long time to shed, but I wouldn't think normal shedding would cause too much stress. Some will stop eating (or not eat too much for a few days leading up to a shed) so it is important to offer some well gutloaded bugs right after a shed. I will sometimes add a little extra vitamin to his calcium depending on when the last dose was. (I have a veiled so twice a month generally for vitamins.) If your chameleon shows signs of stress, I would offer some extra privacy and just make sure he doesn't get too dried out (maybe a few extra mistings).