This just happens,some hens do not make good mothers. I would be cautious in letting her hatch eggs again. Unfortunate that your other broody had her chicks weeks ago,otherwise she might have accepted these ones,she still might. There is no reason to cull her(reading other posts)this does happen very frequently with chickens. Chicks death may have been an accident. Is she a young hen,she could be confused,not sure what she should do. Just keep an eye on her,that is all you can do right now. Or if possible you could take them from her after they hatch,put them in a brooder. If she kills more,than you know she should not be allowed to hatch eggs again. I know this doesn't help as you are worried about other chicks. She will just be a good egg layer,not a good mommy.Three weeks ago, one of my broodies hatched 11 gorgeous chicks. She is what I would consider an ideal mother. When my other hen went broody, I thought she was a little dumb, but would let her have a go at it. Today the eggs she was sitting on started to hatch. I was so excited! She seemed to be doing alright after all. I went out, and the fluffballs slowly increased in number. Then I went out to check on them, and she was standing on the neck of one of her chicks, who by that time was completely dead. There was less than an hour between the times that I checked on them. I am very upset, because that is not a good reason to die... squished by mother. Now I'm worried about the rest of them, but I can't spend all night with her making sure she doesn't squish the rest, and I'm not set up with an incubator to hatch the rest myself. Not sure what I should do, besides not allowing her to hatch a set of chicks again! She seriously looks shocked/confused about the whole thing.
Has anyone else had a similar experience? What did you do?