What we have found is that its best to constantly manage the risk of rats to prevent them setting up home with us. Once you get to the point you actually see a rat they have been there a while and there will be more than one.
We live on a small holding and have a dozen or so hens, we are surrounded by arable farm land.
Mostly we are unbothered by rats but every now and again we will see evidence of their presence, often as mentioned by a poster above just after harvest when they have all been disturbed by the combining/ cultivation process on the fields.
We manage to keep them at bay using the following techniques :-
1.As far as possible make sure there are no food sources for them . (no food source = no rats)
• We store our hen food in bins with tight fitting lids which are always on unless we are using them.
• We have proper scoops for transferring food from the bins to buckets to minimise/eliminate spillage of food in the storage shed.
• New bags of food are transferred to the secure bins asap.
• In the hen hut after our last rat visitation we took the plunge and bought one of the Grandpa type feeders which means there is not an ab-lib supply of food for the rats in the hen hut. They work with a treddle and require the weight of a hen to open the feeder and access the food. http://www.grandpasfeeders.co.uk/products?gclid=CJ2No431h9ECFUI8GwodsmUM0Q
There are a number of people now doing this kind of thing if you google them. We happened to pick ours up second hand at a farm sale. They are expensive..but weighed up against the cost of poison and the hen food you supply to the rats it’s a no brainer.
2. Have predators ready to eliminate new arrivals.
• A few feral cats (or any cats) knocking about is an excellent thing. We have about 3 or 4 at any point in time..a couple we have got from friends (domestic type) and a few which migrate from the farm across the field…that are feral and have adopted us as they get better fed here !. They are not allowed in the house but have access to plenty of sheds and are always fed there. I have seen them take rats. (quite honestly one cat would be enough.)
• Have a trap set at all times. Rats are wise creatures and are wary of anything new. So setting a trap after they’ve arrived takes time to be effective. I have a traditional type sprung trap (large mouse trap). To avoid animals i don’t want getting caught in it, it is positioned in the hen hut in a small wooden box (which I made from scrap timber), with a removable lid and a rat sized hole in 2 corners of the box. It has hen food dribbled around in the box. Rats love cover and this gives them it ..with a nasty surprise ! It is there all the time.
• I haven’t had to resort to poison…but if you do use proper plastic box applicators that again prevent access to other animals and do daily patrols for dead rats.
3. Have as little cover for them as possible.
• You will never stop rats getting under a hen hut…our hen huts are set up on blocks, so that the cats can get under too.
• Our nest boxes are set up off the floor of the hen hut…so cats can get under too.
• Our sheds all have an open door or window or bob hole where the cats can get in and out as they please…so they are always on patrol.
• As far as possible reduce cover in your sheds, leave gaps that fit cats when stacking /storing things, clear up loose bedding and old feed bags as you go along so places they can shelter and hide are eliminated.
Hope these thoughts are of help. cheers stu
One more..if you have a current infestation it could be worth getting someone with a terrier round.