I went to check on my broody. Her chicks are due. She had a dead chick in there with her. I think she pecked it. It looked good but had blood on its side. How often do hens kill their chicks? Should I take the rest of the eggs away? I can hear peeping so I know more will be hatching.
I believe you had said your chicks were due on May 5, so the early hatcher may have confused her or freaked her out, and if it hatched early do you know if the yolk was absorbed fully? I know we have had the rare early hatch which had problems, and sometimes they cheep a lot, the mama hens will then peck at them as if to admonish them to be quiet...it is a sad situation and an inexperienced broody can get too upset and harm the chick. Most broody hens aren't homicidal, they are confused by a situation they don't understand and survival instincts kick in. There is also the possibility that the chick posed a risk to the rest of the eggs in the broody's mind and that caused the issue....there are no absolute rules for causes or actions.
Ideally you will be able to observe the hen for the rest of the hatch and intervene if another problem, removing them to an incubator to hatch is risky but certainly an option and grafting them back to the hen is then something to consider but only if you have time to watch for problems the first day.
Sorry I don't have a definitive answer, just too many variables to consider...I hope it works out for the remaining eggs.