Killing your killer broody may have been a mistake, but of course your flock. My story:
A few hens were broody at the same time. At hatching time they all killed their chicks, except for one chick that I managed to save and raised myself. The same broody hens continued to set on nothing for weeks after that. The next year:
They all went broody again at the same time. I gave them another chance, of course knowing I could have the same problem, but no, the previous years' killer broody moms were now the best moms and co-parented the group of chicks together. Since then:
They had chicks every year and were always great moms. The last one left in her old age had one chick that she continued to protect until that chick was grown and still hang around together until the mom was killed by a hawk (I think).