Sadly some hen's on their first clutch of egg's will kill them.Just like rabbit's.I had a young rabbit kill everyone of 5 of her first babie's.I was so irrate with her to see sadly a graphic pic of a baby with NO leg's.And the baby was still alive when I go to it.Im over that now but nature has some weird stuff sometime's.She raised Alll of her 2nd 4 very well.If you are lucky enough to intervien and save one that's great.Maybe next round the hen will do better and just keep a check for newbie's and take them Immediatley if you can.It sound's like she has issue's and not ready to take any of the chick's in yet.