several chicks just arrived by mail order, one of them is lethargic and not eating, though drinking when we put her beak in the water. at first she just seemed slightly more cold and dehydrated, and was getting some food and water when we moved the other chicks out of the way, but shes been getting worse, and can't stand, and one of her feet is very slightly purplish, especially the outer toe, and she can't or won't flatten her feet to stand even when we support her. Any idea what's wrong or how to help? (out of the other chicks, one was dead and one coughed up some mucus for about two hours before dying)