Momma not caring 4 babies

Question
My rabbit let her babies die. She had babies before and took really good care of the last ones. She's three years old.Do you know why she could do this?

Answer
Amy,

Possibly there was a disturbance like a predator or a rodent nearby that she wasn't comfortable with. Maybe she was stressed because she was moved or handled too much during pregnancy. It is also possible that if there was a long period of time in between litters that she isn't in "mothering mode" any longer. Three isn't too old to have kits, but it is if she isn't kept working.  
It can be hard to determine what caused her to not want to care for her babies without a lot more info. Something in her mind clicked and decided that she had to take care of number one. Her babies then ended up on the back burner and weren't fed.