Cat killing kittens

We have three cats ( a mother and her two adult daughters) give birth to kittens within one week of each other. The daughters were in the same room and withing a week and a half, they combined their litters and took turns caring for them. Now one of those cats has killed two of its kittens. She was sitting on them. I don't know if one suffocated or what, but the other one appears to have a broken back, she is still barely breathing. These kittens are about 4 weeks old. Why would this cat do this?

Not knowing much about birthing cats and what not. But could this have been an accident?

Maybe it could have been an accident. She was sitting right on the kittens and one of them was meowing as loud as possible. That's what got our attention. Now to us humans, that would seem to be intentional. But who knows what a cat thinks. The poor one with the broken back is still breathing. I thought it would die by itself by now. I'm not sure what to do with it. Or with the cat that killed them.

The one that is injuried needs to see a vet asap. Chances are if his back is broken he may need to be euthed.

I've noticed that new mothers aren't very good with the common sense. We had a mother (1st time mother) who would put her kittens in the worst places possible. We kept moving her kittens and the nest placement got worse. At one point we found them under the hay feeder...half the kittens were trampled! I would think your mommas aren't being as careful, nor realize teh consquence of laying on their babies. This year probably won't be a good year for your momma cats and their babies, but they will get better with practice!!!!

In heaven's name, why on earth hasn't that 'barely breathing' kitten been to a vet - like half an hour after you found it like that? How cruel can you be!!

I'm struggling to understand how an adult cat could cause a broken back in a 4 week old kitten. At 4 weeks the kitties would be reasonably robust (in my experience) and if an adult cat was to sit on them they'd have the ability to wiggle out.

Is it possible that a person or child in your house could have accidentally stepped on or sat on the kitten, as at that age they are starting to climb and do tend to get underfoot unexpectedly.

I do agree with the previous poster - please have a heart and take the poor kitten to the vet immediately.

Please be aware that there are low-cost options available for spaying your female cats - assuming you are in the UShttp://www.lovethatcat.com/spayneuter.html

Please take the kitten to the vet if its still alive and have it humanly put to sleep. I'm wondering if something could have fallen on the kitten? A heavy book, or one of the cats might have jumped down and accidently jumped on the kitten.