hi sorry to hear about the loss
im a vermin controller and deal with this sort of thing all the time but its never an easy job when it comes down to rats,
unfortunatly for us rats are very sensative to change and they are very easy to disturb but if there is a permenant food source they will do anything to keep contact with it
in many cases you have to feed them to stop them, move them somewhere else and then deal with them poisoning works but usually not a very quick method and very costly i prefer to use fen traps as there very strong and instant kill but they can be deadly to your fingers to.
as for your aviery floor turn it over and add rubble and comact it as much as possible this wont stop them but it makes it a bit harder and more noticable if they return in the same way
if you are going to poison use the block kind as they have to chew it to release it so it cant be stored and most are very affective.
hope this helps
good luck




