Yea, one of my rats did the same exact thing.. She raised all of them up till today and they all opened there eyes, and when i went to check on them, she had killed about 5 out of 11... And brutally, cracked there skulls, and it was just terrible, and so i didnt risk anymore getting killed so i just put out the mother and am going to try and wean these guys early.. Its better than risking more of them getting brutally killed... I would rather just one rat die for all of them to have a better chance... I want to use them all as breeders (i think i got all females...)