We have a mouse problem in our woodshed and horse feed store. I just put some of the horse feed onto the bait hook, fresh stuff mind, as the older drier stuff doesn't pong as good. Anyway in 2009 I got 56 mice. So far this year I've had 16 and I only set two traps. If you go with the trap route though I would suggest wiring the trap to something solid as a cat could take off your kill along with the little nipper. I lost "Ol' Faithful" and "El Bruto" to some bigger scavenger, found El Bruto a few months later but the rust had gotten into him and he was never the same after that.
Got a pretty good trophy collection now. 3 pairs of gloves and I'm working on a hat now.
Seriously though about the poison, our dog ate some, but he's a labrador cross and in good health so we noticed the decline straight away. Got him to the vets after a hornet stung him and the bleeding wouldn't stop. She asked if he was acting slow and lathargic and we said yes but put it down to his advancing years. She explained that he was dangerously anemic and concluded what he'd eaten and put him on a course of medication. Now he's back to his old self. Wish I could say the same for the other dog that our nieghbour had that ate the poison, she died.
In my opinion traps are more humane and they're a one shot deal like you're after.
Mars bars? On a trap? Are you deranged!!!? :yikes: But that's chocolate