I feel sick...

[Mike41793]

I personally use cervical dislocation, which I feel is the most humane and quickest method. Place something like a screw driver, chopstick or butter knive behind the head and give a firm, quick yank at the base of the tail. They die instantly.

This.

And when theyre babies their skulls are like paper thin and a strong flick to the skull will kill them.

CO2 isnt as an effective method for killing baby rats. Their lungs dont need as much oxygen so you may gas them an *think* theyre dead when they really arent.