Vermin control in farm buildings

As the weather is starting to get colder, vermin such as rats and mice will be looking for somewhere to spend the winter indoors, and nowhere is better than a farm building that might have grain or other foodstuffs in plentiful supply.  Buildings can be made vermin-proof by sealing off any points of entry and setting traps to catch any rats or mice that may have already pitched up for the winter.

Take into account children and domestic animals if using rat poisons.