Winter grain diet?

I thought I'd had a brainwave a few months ago...How wrong was I???

I worked out that I could get 70kg of grain for the price of 40kg of layer pellets, so I thought to save money over the winter months when sales are lean and the birds aren't laying, that I would switch to an all grain diet for the winter. Brilliant idea in principle, the birds loved the feed and thrived on it, keeping them nice and healthy and not getting fat!, but one thing I didn't account for was rats!.

Now, we've not seen a single sign of a rat here for 2 years...I'm sure we had a few, but never had a problem. Within a couple of weeks of the all grain diet, holes started to appear from under the shed, under the fence and in the compost heap (my fault, this one, should've kept turning the compost heap over, so the activity would scare anything from living in it (other than worms). Now I have spent more on poison than what I had saved on the feed costs, so all grain diet was definitely a false economy for us. Needless to say, that now the birds are split back into breeding groups and being fed breeder pellets (fancy feed...the birds love 'em), with all feeders taken out of the runs at night. Over the last week, there has been a reduction in rodent activity, so hopefully the poison is working, I'll now keep poison down all year round and not be so complacent about not having a rat problem!