Who wing tag's your chicks?

[steffpeck]

I am looking for something to use to use to ID the lines in my Barnveleder's and my Orpington's. I have tried the zip ties but have come way to close to them getting to tight before they are changed to a bigger size. I would like to use something that I can ID them with and not have to worry about it again. I have heard of wing tag's. Does anyone use them? What are the Pro's and Con's of them? Where can I get them? Thanks for your help!!