So sorry your hen is having a rough time. At least now you have a little chicky, hopefully two. Has this hen been broody before? Has she successfully hatched out chicks before?
The hen that hatched the chick that died had been incubating the eggs. After the chick died we put the eggs under a different broody hen and brought her whole nest (a cat carrier) inside in case the chicks got too cold like the first one. Well, when the second chick hatched she tried to kill it, luckily we heard it and came to the rescue and set up a brooder inside until the third one hatches. Then they will go to an outside brooder in the coop.
The first broody has not been broody before she is a Pullet.
The second broody that tried to kill them before went broody last year but I broke her. This year she was broody for a week then quit, then less than a month ago she went broody again and I gave her eggs but it hasn't been 21 days since she's been broody so I wonder if that's why she rejected them?