Mice are often hard to get started so first do not give up and find what work for you.

Cannibalism can be linked to several things

Overcrowded living space - Diet - Lack of security etc

For ME what I found was working best was to have smaller groups 1.2 in small cat litter pan.

They are house in a rack like this one

http://stewartreptiles.com/Articles/...eding_Rack.pdf

Since I have been breeding them using this method I have experienced 0 cannibalism and my litters average 14-18 babies.

All you can do is to try and find what works for you once you do it will be a smooth ride.