Now is the time to get a strong feeding regime going so they get zapped in the hardest months when there is little else to eat and reproduction is at its lowest rate of success .
This plaster of Paris and Bicarb idea kind of amuses me ..
I've seen it on the likes of " Yahoo answers and Wikki squeaks " but really..if it were that effective and cost effective the big boys would have been advocating it years ago . so would have farmers ,grannies and granddads all over the world.
Think on this ..... rats chew their way through brick walls , wood ,plastered walls and all sorts of plastics .
If there is a trace of food stuff or fat on it on it they will swallow it & digest it in their stomach acids .
Rats cannot be sick ( Thats why Warfrin etc works so well ) so the stomach acids must be some quality stuff to dissolve what they eat.
They cant usually chew through salt glazed drain pipes but do a nice job of the haunchings & brick work to get down into the sewers .
I have numerous friends on another site who are professional pest controlers ..fully registered and licenced in the arts of terminalting our friend ratty etc.
I'll ask them for advice and permission to put their replies here .