I use them, colored ones, as temporary bands, to ensure I have everyone when I'm treating the flock (worming, dusting, etc), and I use pink or blue when I want to see if I'm guessing right (boy or girl)....I didnt have anything else around when I needed them, thats how come I started using them. You just have to be aware, every day, of their growth if they're young - since zip ties arent flexible, you can cause injury/strangulation of the limb, if left on too tight. I like them, but only for my own birds, that I handle all the time. I wouldnt rehome a bird with a zip tie on it. (They also could potentially tighten by accident). Personal choice.