Yikes!

So last week I paid a visit to a local reptile breeder to pick up some feeder mice. Since the drive is an hour away I took about a dozen mice including 2 pregnant females that the breeder suggested would provide me some hoppers in the next few weeks. I took the two pregnant females and put them in one tub with Aspen bedding, water, and food. The others I had in another tub until I used the last of them the other night. As of last night neither of the two females had laid their babies yet. Then just now I come into the room where I have them to discover the larger female dead and the other one eating whats left of it's head! I've been very good about making sure there was food and water in the tub at all times and I know they had a few pellets of food in there last night. Is this common for mice to canablize another? Is it possible she killed the other then decided to eat it? Was it my fault for putting the two together? Should they have been separated?
Any suggestions welcomed as I was considering actually breeding some of my own but after seeing this I don't know.

The one that died could have died while giving birth and the other one is just cleaning up.

Mice are harder to breed than rats, I tried for a few months, but only one rat got pregnant and she died giving birth ._.
I now breed rats and haven't had any fatalities in almost a year.


Also, check the temperatures, mice are very sensitive to high temps, even just being in the 80's could kill your females.

I am solely a rat relationship promoter. Easy to do and never have any issues. One female is a bad mother and let a couple die. So I pulled them and place with another mother. No issues so far.

It is possible it's just bad stock, and stress. I suggest getting the best mice that you can find, and try breeding them. That's always my suggestion. I personally breed mice for show, and feeders. So I have very high quality animals, that almost never have litter problems, or personality problems.

There are also high quality feeders vs low quality feeders. There's almost no way to tell just by looking at the mice themselves.

Thanks everyone for chiming in. I didn't really have plans on breeding mice for feeders, in fact in the future I was thinking rats would be easier and the comments posted here seem to support that. I've been mostly feeding f/t but having recently run into a few new hatchlings that were insisting on only live mice I grabbed extras for the others as well. It was the breeders idea for me to take a few pregnant mice, I was actually reluctant and now I wish I hadn't. I don't think she died giving birth as there were no signs of this but she may have died from complications related to the pending birth.