The chicken's food layena, has to much calcium for the chicks to handle, their kidneys will shut down and die. Why are you feeding a 14 week old laying formula just out of curiosity. It too, might be to much until she starts laying. If I had this much disparity between ages, I'd feed a flock crumble for like ducks, geese and wild. This way you have the higher protein without the added calcium. Good luck.