The yellow Chicks. Polly is smaller than Holly and Molly. Holly and Molly are the same size as the red chicks. Holly Molly Polly The red Chicks. Hallie and Sallie have a similar appearnace, except Hallie's head is a bit darker. Callie's back is darker and she's got more markings on her wings, so far. Callie Hallie Sallie So, were assuming they're about a week old? The yellow chicks are Leghorns? And the red.........?