The chick on the right, in the back, is not growing. I've had them all a week and they were the same size when I got them. They were four days old. The one in question doesn't seem to eat, but rushes over when the others eat and pecks at the food. She must be eating something, she does poop but it's small. She loves for me to cuddle her on the heat pad. Any suggestions? I don't want to lose her. Thanks.