Here’s a simple how-to video on how to put on leg bands. This is the best way to identify your birds or keep track of multiple flocks. My birds all look identical, each leg band has a highly visible number making it easy to know which hen is which. They come in various sizes and colors so it’s not at all hard finding your specific preference.
Many chicken keepers use brightly colored zip ties, I did too for a while, but they are hard to get on and off and they get brittle with age.
You can get leg bands at Murray McMurray