if a mouse fineds its way out it will go in the trap and out at will iv had this the way to stop this is to squeeze the
bottom as john says a bit so they can only just get in.
to true bud good post blocking them in is no good.i had to leave a terrier in the ground years ago to go and get a spade when out for a walk.was 1hour from home left my coat out side one of the holes when i got back he was sat there waiting for me.
there's been a lot of dogs missing since iv been on this site the last few years.you don't seem to here of many being found.makes me wonder if they are being put down if there workers or from lads that work there dogs