We just got baby chicks yesterday, from Tractor Supply. This was the very first day they were carrying them, so they are probably just a few days old. Anyway, I noticed yesterday that one of them has something that looks like a very thin piece of string and its a tan color. I am guessing it's the umbilical cord? It's still there today. Should I do anything about it or just leave it? Wasn't sure if it got stepped on or pulled by another chick, if that could hurt it, or if at this point it would't matter?