With our old Shepherd the routine was that I got up at 5am, let the dog out, started the coffee pot, let the dog back in and so on.
This one morning opened the back door to let the dog in, it's pitch black, I saw something in her mouth and couldn't tell what it was. "What do you have girl?" she immediately went into the GSD death shake. Needless to say, I had blood all over me, she had blood all over her white coat, my porch and the back of the house looked like a mass murder took place.
I can't tell you if she she tried to decapitate it but it was certainly shredded. She was fed kibble, not raw, we had a smaller dog in the house but no cats or rats. She did chase mice, lizards, birds though.
Oh and that was a lovely way to start a morning before my first cup of coffee.