Killing in the Benedictine Rule Is the injunction in the Benedictine rule “Deinde non occidere” interpreted to forbid the killing of brutes, or only humans?
The quotation comes from the beginning of Chapter 4 of the Rule, where St. Benedict lists the "instruments of good works". The list begins by quoting several of the commandments:


  In the first place, to love the Lord God with the whole heart, the whole soul and the whole
  strength.
  
  Then one’s neighbour as if oneself.
  
  Then, not to kill.
  
  Not to commit adultery.
  
  Not to steal.
  
  Not to covet.
  
  Not to utter false witness. 


So it seems that these "instruments" were intended to be understood just as the commandments were ordinarily understood. In particular, this commandment forbids killing people, not lower animals. 

The Rule also allows the sick and infirm to eat flesh meat (Chapter 36), which would seem incompatible with a general injunction against killing animals.