The traps are failing to go off 60% of the time, and all the peanut butter is gone.
Sounds like the trigger needs adjusting. You want it so that ANY contact, no matter how light, will set it off.
chris
In my bachelor days I had a "trap line" of a dozen traditional wooden Victors. I had the triggers set so light that they'd often go off if I walked by them too fast. Every morning half of the traps would be full.
I eventually got tired of the BS and brought home a Manx cat..................no more mices.
