I have just purchased a set of bags and was wondering what to use as filler. I have searched on here and the concencus was either plastic beads or sand. Really I need inert material as was considering rice/wheat/maize but obviously no good if gets wet or not rodent proof. I don't need much only a kg or so for the rear bag which is the one which will be used the most.
Anyway I had an inspirational thought: really fine type gravel or sand would be ideal and a quick look in Pets at Home revealed a huge varriety of sand and gravel of different sizes and textures which is used in aquariums. Most of it is packed in 2kg bags, which have clear packaging and better still the packets are squ=eezable so some idea of how it will behave in a bag. Anyway I settled for a 2 kg bag of neon Pink £3.50p which looks quite fine so will try and report back.