We have eleven day old chicks, all of whom seem to be thriving but one. She is smallish, and her foot bones don't seem as firm. She often lies down. When she is lying down, she curls her feet up. But when she stands they do extend straight, so it isnt curled foot? Would one chick get rickets if the others didn't? 1: Does anyone know what this is, or what causes it? 2: Should we isolate her so the others don't pick on her? 3: Is there anything else we can do?