I've never seen rules on what you CANNOT use as legbands, only that birds need to have numbered legbands. That said, I have never seen it actually BE required (as in a bird is DQed or does not place due to lack of band). The reality is that many people use different methods of marking their birds, and short of shaving a number into their feathers or permanently inking a number onto their feathers, I don't think a judge will care unless it impacts his/her work. The only time I have seen them truly needed is when birds are caged together, as is common with trios. Then, how can the judge mark which hen/pullet places over the other (such as BV or BB) if they do not have legbands? The reason I suggest leaving them off is the chance of losing them, and it sounded like they were special to you. I had assumed that the birds were used to them. If not, you DO want to be sure they won't peck at them and try to eat the sparklies.