Has anyone had any experience with these? I really need to use something with numbers to keep my records and my babies straight, and these seemed great, but I cannot figure out how I would get them off without hurting the chick's leg. They are easy to close using a needle nose pliers, but once closed I cannot get them open again and they are quite small so they will outgrow them fairly soon. Is there some trick that I do not know about? Luckily I have not put any on any chicks yet!