This is in response to the original request of a mammalian example where a female kills her own offspring. I have myself been looking for examples of this, and have found it very difficult. I have yet to find a peer reviewed article documenting this occurance, but it is well known to occur in Norway rats
http://www.ratbehavior.org/infanticide.htm, at least those kept in captivity. I have also heard of cases in Kangaroos where the mother (who is capable of superfetation) will remove one young from her pouch in order to allow a second to continue developing when resources are scarce. While not a mammalian example, I believe coots regularily kill a portion of their clutch. Hope that helps!