The correct procedure is to lay the bait where the rat can get at it but to
prevent, as far as possible, access to other creatures particularly domestic
pets. The local rodent control operative does this by using a 500mm length
of pipe with a diameter of some 100mm with half of each end blocked off. He
places this in a run he has identified that the rats use. Initially it may
attract additional rats since the poison is designed to be very attractive
to them. Usually all have gone within a fortnight. To be successful you need
to remove other food sources such as birdseed. Rats are by their nature very
cautious and need time to pluck up the courage to eat. A slow acting poison
is used so that the rats ingest a fatal dose before any symptoms become
apparent. 100% success rate here!