This incident occurred in less than 15 minutes, between a male and this hetero beige female that had been together for 5 months. As you can see the damage didn't look that bad when I found her.
In the second and third photos I have cleaned up the wounds a bit. The blue arrow in the second photo is pointing to a wound that went through the skin and was sucking air in as I was pulling fur from around it.
This female had wounds on her chest, back, head, thighs/legs, belly and vaginal areas. This type of beating happens to every breeder at least once. Nobody has any explanation for why this happens and it is always a horrible thing to find.
Thankfully this beautiful girl recovered fully, had complete fur re-growth in all areas within four months and went on to take reserve color class champion at show.
I have seen cases where males in both runs and trios that have been producing for years have suddenly killed the females, or killed their babies for no obvious reason. I have also seen females turn on and kill a male or maul their kits. One of the things that may cause a situation like this are males smelling another female in heat and attempting to mount the one they have access to. Of course she will resist and may run or fight with the male.
It is also worth mentioning that if you house a group of males in the same area as a female (this includes your entire house - they have an excellent sense of smell!), there may be fighting.