My babies are 3 days old. There are two, a white and a brown, who will about once an hour, stretch really tall up on their toes and make a distinctive Peep Peep Peep. I am pretty sure it is always the same two. The brown is a pretty rich shade of brown and the white is one of the bigger ones and very fluffy. So can't be 100% sure, but pretty sure it's just those 2 when I hear that call and look to see. Are they roosters? Can you tell so early? It is a very distinctive stretch-to-the-sky and peep.