I'm currently using Bailey's Best British Oats, mixed flake (barley, maize and pea), barley (they eat more of this so I add more than is in the mixed flake), mixed wild bird seed, Wafcol Greyhound Maintenance dog food and Breederpack broken dog biscuits (like Bonios etc). The Wafcol is not from a special shop, just a farm shop. You can use any brand you like really as long as you get good results and the mice eat it! It might be worth bearing in mind though that working dog food has no VAT on it.