we put dif colored tie wraps on ours when they were chicks.. But I have bad eyesight and cant see their legs. If I had to do over and have chickens would have gotten diff ones.. but can tell some by their dofferent "voices" or whinings. LOL
I've got two of them, and the one pictured above and in my avatar is my most inquisitive and friendly of the entire flock...almost like a fluffy puppy the way she watches and follows me. They will definitely have different vocalizations and different feather patterns with which you can tell them apart.